Free download. Book file PDF easily for everyone and every device. You can download and read online Earth Magnetism: A Guided Tour Through Magnetic Fields (2001)(1st ed.)(en)(151s) file PDF Book only if you are registered here. And also you can download or read online all Book PDF file that related with Earth Magnetism: A Guided Tour Through Magnetic Fields (2001)(1st ed.)(en)(151s) book. Happy reading Earth Magnetism: A Guided Tour Through Magnetic Fields (2001)(1st ed.)(en)(151s) Bookeveryone. Download file Free Book PDF Earth Magnetism: A Guided Tour Through Magnetic Fields (2001)(1st ed.)(en)(151s) at Complete PDF Library. This Book have some digital formats such us :paperbook, ebook, kindle, epub, fb2 and another formats. Here is The CompletePDF Book Library. It's free to register here to get Book file PDF Earth Magnetism: A Guided Tour Through Magnetic Fields (2001)(1st ed.)(en)(151s) Pocket Guide.

There note badly no Congratulations in your Shopping Cart. Or, want it for Kobo Super Points! Slideshare is rides to Add information and kind, and to see you with real account. If you perform trying the quality, you 've to the book of admins on this URL. Poster size: 26" X 38". The water cycle, the oxygen cycle, the lunar cycle, the cycle of the seasons, and the rock cycle are all depicted in detailed diagrams.

Cycle on! This colorful poster details the many poisonous plants and their locations around the world. Physical symptoms, level of toxicity, and known therapies are also noted. Poster size: 26" x 38", laminated. It also contains a section on the father of the periodic table.

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The elements are arranged by their atomic number, starting with the galactic center and circle outwards. This poster explains how the elements are used by bones, blood, metabolism, in genetics and disease. It includes the Bose-Einstein Condensate states as well as the more well-known ones solid, liquid, gas, plasm. Information sheet and two 8.

Actual photographs of meteorite fragments billions of years old are accompanied by detailed descriptions of their composition and their discovery sites all around the world. Other sections talk about meteorite hunters, the Peekskill Meteorite Car and aspects of photomicroscopy.

A world map shows all craters plotted geographically with the names of the craters, latitude and longitude. Sorry Pluto! Relative size and distance is explained along with a conversion scale of metric and US units. The number of moons, if any, are shown along with the astronomical symbol. This poster measures 45" x 18".

Complete with three timelines which lay out occurrences since the Big Bang. Our galaxy, the Milky Way, is used to teach students about Red Shift and what that means in identifying other galaxies far, far away. Poster measures 38" 26", laminated. This unique chart presents ingredients of sound including pitch, tone, pressure and vibration.

An activity guide provides ideas for experimentation, particularly suitable for middle grades. With this exciting visual aid, students can explore the unique relationship between the unseen electric and magnetic waves surrounding us. See the difference between wavelength and frequency scales in addition to understanding radio and microwave usage, x-ray and gamma ray absorption and much more! Accompanied by an explanatory sheet. Use as a reminder to students about what goes into the trash and what goes into the recycle bin, electrical usage, and daily transportation.

The poster measures 38" X 26", laminated. What is the Greenhouse Effect? Comes with double-sided information sheet with questions and answers for teachers or the interested layman. Includes a 4 page info sheet with questions and answers. The sources covered and given an in-depth discussion about are: solar, wind, geothermal, tidal and wave motion, methane hydrates, biomass, smart grids, hydro power, nuclear, coal and biofuels - green crude.

There are graphs covering renewable energy ; and a section covering energy salaries and incomes for the U. This is a great addition to our environmental series on how to save our planet! Includes sheet with additional notes and review questions. What two sources do we get Stem Cells from? What benefits can we see from Stem Cell research? What are the Pros and Cons of Stem Cell research?

Questions provided will bring about discussions with your students as they learn about Stem Cell research. The time line shows the many years of scientific research involved with where we are today and some of the health issues that have been impacted. An informational sheet for the teacher is included. This poster measures 26" X 38", laminated. Nine of the pioneers in electricity are also depicted. Teacher information sheet included. It is vital students learn about the planet and how to take care of it. The shape of the Earth and its core have a specific impact upon Plate Tectonics, Volcanoes, Earthquakes, Geysers and more.

Stunning images of the volcano in Iceland that erupted in make the backdrop for this poster perfect for the Earth Science classroom. This poster measures 38" X 26", laminated. Other uses for light and other observable phenomena are also presented. Includes sheet with additional discussion material and questions for review. Each poster details its subject under the microscope and into your classroom!

The large viewing area on the 12" and 8" Tanks allow students to easily see what is happening without a lot of materials! It demonstrates an incredible amount of experiments while being visually exciting and cost effective. May be used over and over again. A Teacher's Insert is supplied.

Students from Kindergarten through high school will enjoy the experiments they can accomplish. Add a 12" Expansion Kit Product to complete a wider variety of hands-on science experiments. Included are experiments related to: color, plant growth, diffusion, pond life, etc. The lessons can be adjusted to different levels of investigation. A complete materials list for each experiment is included for the teacher. The experiments can be modified by teachers for their particular science lesson objective and needs.

A complete material list for each and every experiment is included. Use any of the Volumes along with either the 8" Jr. The fully developed lessons may be adapted for different levels of investigation. A large expansion kit and a 4 oz. The fully developed lessons provide lots of room for independent investigation. Use them to grow plants, investigate cells, monitor water absorption, etc. Let your imagination go wild! The activities will help students discover how easy and fun science can be!

By using a culture of Daphnia, obtained from your Biological Supplier students test commonly used drugs and observe changes in the circulatory and nervous systems of the organism. Enough materials are provided for 30 students working in pairs. Includes SDS. This intriguing kit provides a clear and impressive revelation of the substances inhaled into the lungs of smokers and those in their vicinity. The specially designed smoking apparatus is utilized for capturing smoke in a filter and extracting it into an alcoholic solution that can be poured onto a filter paper and evaporated.

The kit enables students to observe and safely smell some of the substances in cigarette smoke, increasing their awareness of the hazards of active and passive smoking. The experiments draw smoke through a high efficiency fiberglass filter which collects the tars and nicotine. Higher level students can use the kit for sophisticated chemical analysis of cigarette tars.

Kit includes 25 filters, molded plastic lid cigarette holder and base, aspirator bulb, color chart for quantitative determination of tar content, and instructions for 5 complete experiments. Cigarettes not included. Activities demonstrate the radical effects of heavy metal poisons on enzymes, and discussion materials provide additional information on the types of poisons and their mechanisms.

Enough material is provided for 12 groups to perform a variety of experiments. SDS available. As always, the student will answer the question under his left thumb when the ball is caught. A great way to practice and learn! Complete answer guide and suggestions for play are included. Includes repair patch.

Circumference measures 48" when inflated. No latex. General drug and alcohol questions are included as well. This ball is not suitable for a typical classroom. This durably built, inflatable ball will have your students begging to learn more and further discuss drug and alcohol use. Simply toss the ball around the room, gym, playground or at home, and the students answer the questions found under their left thumb. Students will answer the question found under their left thumb after catching the ball. How big is your heart? Which vessels return oxygen-depleted blood to the heart?

Made with a patented light-weight material that mounts with ease and removes cleanly from most surfaces. Includes Wall Sticker, 49 magnetic pieces, and mounting instructions. The durably built vinyl ball will provide years of Nutrition education information for the classroom, playground, or home. Name one physical benefit of exercise. How many calories per gram does alcohol contain? Tumble the cube and perform the exercises on the top of the cube with the number on the cube. Good for in the classroom, gymnasium, or even outside.

This durably built, heat-sealed 7" vinyl cube can provide imaginative fun and exercise! No latex! Hands-on experiments with tactile and visual accessories facilitate student interaction and make learning fun! Includes a 44 page teacher's guide. The kit contains directions for 26 handson activities and 42 different components for exploring basic scientific ideas such as light, color, magnetism, motion, air, plants, and water. No scientific background is needed to present these simple activities.

The health activity projects on the next three pages were developed by the Lawrence Hall of Science around health topics such as breathing and heart fitness. As students follow the activities, they learn and apply methods of scientific investigation. With these activities, students will learn the importance of their good health, and the choices they can make to stay healthy. These activities also incorporate math, social studies, communications, and language arts skills for further enrichment of any curriculum or lesson plan.

Reactions times are measured in hundredths of a second. Record elapsed time with either the hand or foot switch. Comes with instruction sheet. Requires 4 AA batteries which are not included. Kit includes: breath control meter, lung volume bag, breath volume bag and valve, meter tape, mouth pieces, chemicals, 3 charts, plus an Teacher's Packet with activity plans.

Additional or replacement supplies sold separately. The lung volume kit gives students the opportunity to understand their own physiology more thoroughly. Kit includes: 4 each: durable plastic bag calibrated to 6 liters, mouthpiece, and mouthpiece holder. Kit will also aid in demonstrating the effects of conditioning. Kit includes: 1 mouthpiece set, 1 rubber band, 1 connector, 1 lung volume bag, 2 valves, and a complete instruction guide.

May be adjusted for different strength levels. The many activities outlined step-by-step in the Teacher's Guide will improve students' awareness of their own flexibility and strength. This lab kit includes: limber gauge, grip tester, gripper, splints, 3 charts, miscellaneous parts and chart labeling supplies.

By monitoring heart rates and recovery times and collecting data, students measure the effects of exercise and the impact of added weight on heart rate. Kit contains stethoscope, extra weight backpack, and Teacher's Packet with 5 activity plans. Topics include learning how a lens affects vision, measuring field of vision, and capturing sound waves. Kit contains vision disk, pinhole viewer, lenses, eye chart, masks, flashlight, rubber balls, an extensive packet of activities and Teacher's Guide.

Using a reaction timer, students measure response time to various stimuli including light, sound, and touch. Materials are included to allow students to develop their own personal training programs and to chart the results. Ultimately, students relate reaction time to general health and mental alertness. Kit includes reaction timer, game board and pieces, chart, packet of activities, and Teacher's Guide. Reaction Timer - This battery 4 AA batteries included operated digital timer measures reaction time in hundredths of a second.

Response switch can be used to measure reactions to light, sound and touch stimuli. Includes instructions. Activities challenge students to determine the factors involved in safetyrelated problems associated with balance. Lab includes investigation of insulating capacity of different fabrics. There are 3 different traits to select from. Each trait is represented by a corresponding facial feature which you can affix to the demonstration board without glue, magnets, or fasteners. The resultant offspring will show the dominant detached earlobe trait! Eight lessons all together. Clear enough for elementary school — detailed enough for AP Bio!

Using calipers, measuring tapes, charts, and other supplies, student can compare growth trends for many different age groups. Circumference is 48" when inflated. Sample questions: Which organ is sometimes called "grey matter"? Which vessels return oxygendepleted blood to the heart? Be the player to collect the most Digest-O-Bucks as you travel from the esophagus to the rectum answering questions about the Digestive System.

Contains two plastic replicas of the digestive tract plus an activity guide written especially for kids. Younger students learn basic anatomical information, while older students expand on the activities. Book illustrations and hand-out diagrams for the digestive system are boring. The Digestive Walk-Thru mat measures 70" x 70" and comes with a convenient storage bag. This is a perfect review and quiz product for your students. A teacher's guide provides additional information, activities, and assessment sheets for the classroom.

Made of soft PVC vinyl. Get your students up out of their seats and literally walk the path of blood through the heart! The Human Heart Walk-Thru mat measures 50" x 60" and comes with a convenient vinyl storage bag. A Teacher's Guide provides additional information, activities and assessment sheets for the classroom. The teacher's guide includes: comprehensive lesson plans, easy hands-on experiments, reproducible student worksheets, assessment notes, extension activities, background information, references and detailed tables and illustrations.

The large model is keyed to an instructional CD and a workbook to help students identify internal organ structure and function. The transparent plastic cover is markable for instruction purposes and represents the outer skin. Appropriate for health and science classes. In conjunction with the 76 page Teacher's Guide, this highly interactive model allows students to conduct activities on the functions of each system. Nervous System: Registers sensory responses. Digestive System: Effectively illustrates the passage of food through the body.

Circulatory System: Latex heart can be pumped, forcing fluid through transparent tubes representing blood vessels. Urinary System: Functioning of kidneys, bladder, and urethra are demonstrated. Respiratory System: Demonstrates inhalation and exhalation. The Inflatable Torso Model promotes interactive play with its durable but soft inflatable parts. There are 5 inflatable organs included: the brain, left lung, right lung, heart, and digestive system.

Also included are fascinating facts for additional educational value. The BiO2 Inflatable Torso Model comes complete with a detailed teacher's guide and related worksheets. The exterior depicts superficial muscular and skeletal features of a young boy. The torso opens to expose respiratory, circulatory, digestive, urinary, and nervous systems.

Internal organs are removable for closer study.

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Includes: page Teacher's Guide with extensive back-ground information, numerous activities, observation, and data sheets. Model is also available with four anatomy models, each with an accompanying activity notebook See below. Also available in Spanish and French. These magnified structures facilitate hands-on learning as they are correlated to a full-color overhead transparency with overlay. Each model in the series contains the supplemental materials listed in the description of the Model Activity Sets at the top of the page. A separate diagram panel also shows components of the retina.

A side view of upper and lower teeth makes this a "three models in one" teaching tool. The model together with the activity guide and transparency incorporates a series of activities. A crosssectional enlargement of the human skin illustrates the skin layers, hair follicles, sweat glands, nerve endings, blood vessels, and more. Each set includes a 24" x 18" markable model made of durable vinyl, a Teacher's Guide containing background information with teacher-developed activities, a related glossary, a key to the model, color transparencies, and a backline master.

A cutaway view of the interior of the heart can be felt and studied without the complications of dissection. Process is reinforced with a colorful three-overlay transparency of the heart. Trace vessels throughout the body while viewing an enlarged cutaway section of a vein and an artery. Activity set includes a 18"H X 24"W model and a customized activity guide with background information, glossary, key, color transparency, and a blackline master.

Each model in the series contains the supplemental materials listed in the description of the general Human body System Model Activity Sets at the top of the page. Learning is enhanced by the cutaway sections and enlargements of the stomach and intestines which further illustrate the system. A close examination of the human brain with a removable transparent overlay defining the brain lobes is included. Diagrams illustrate the location of the brain, spinal cord, spinal nerves, dendrites, axons, and synapses.

The dissected kidney is enlarged to illustrate the cortex, pyramid, calyx, and papilla. Seven endocrine glands are depicted in whole and magnified sectional detail, as are the closely related organs. Included on the model are the pituitary, thyroid, parathyroid, adrenal glands, pancreas, ovaries, and testes.

Set includes 24"H X 18"W model, activity guide, and a color transparency. Illustrate the functions of the body's major systems. Each Model Activity Set includes a full-color 24" x 18" markable model of durable vinyl and an activity guide with background information, basic understandings, teacher-developed activities, a glossary, a key to model structures, color transparencies and a black line master. Each Model Activity Set consists of a 24" x 18" markable model of durable vinyl and an activity guide which includes background information, teacher-developed activities, a glossary, a key to model structures, color transparencies and a black line master.

Grades , Ages Valuable graphic aid for discussing health issues and pregnancy. Aids in the discussion of women's health issues and pregnancy. Each model in the series contains the important supplemental materials listed in the description of the Human Reproductive System Model Activity Sets at the top of the page. This model features lifesized, detailed, and accurate representation of the anatomical features of the fetus and its mother. The sequence on the model illustrates the successive development of the fetus from the sixth week after conception to the 16th week.

It is a great graphic instructional aid on reproduction topics. It depicts all male reproductive organs, plus a magnified sectioned sperm. Enlarged views detail the five phases of mitosis. Includes cytoplasm nucleus, nucleolus, chromatic threads, centrioles, aster, spindle, chromosomes, and centromere. Two magnified ovaries show ovum development.

Accompanying activity guide facilitates learning about this basic human body function with comprehensive information and discussion materials. This model reflects dimensions and spatial relationships that are anatomically accurate. The scale of the Birth Model is life-sized. The model shows the delivery of a full term fetus with the hands of the doctor assisting in the birthing process. A detailed illustration shows a normal fetal birth position displaying the placenta, umbilical cord, cervix, and vagina. Visualization and understanding of meiotic cell division are promoted through enlarged views of chromosomes, cytoplasm, and chromatic and polar bodies.

Dimensions and spatial relationships are anatomically accurate. The model shows a full-term fetus positioned within the maternal body. A removable transparent plastic shell illustrates the amnion "bag of water" in which the fetus rests. The model also contains a detailed enlargement of the placenta in semi-diagrammatic form.

The enclosed key provides proper nomenclature to each of the parts of the model. In addition to the model, black line drawings are provided for visual reinforcement. Each model in the series contains the important supplemental materials listed in the description of the Human Reproductive System Model Activity Sets at the top of the page The pads are reusable and there is no need to melt sticky wax.

The covers close up for the day.

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Made to last, these dissecting pans are great for general use. Available in several different sizes and styles, with or without wax wax is a mixture of black tar and white wax. Each pan has smooth, rolled edges and is stackable. When resurfacing, put the pan on a hot plate to melt the wax. Not dishwasher or microwave safe. A built-in recession in the top allows for secure stacking of multiple pans.

The pan is also available with blue pads. The heavy-duty leatherette cases will hold essential dissection instruments. The molded plastic case's capacity is variable. The cases are an excellent product to help store, protect, organize, and display tools, helping to cut down on valuable classroom time. Instruments not included. Watch the excitement when your student dissects an earthworm, frog, or grasshopper. Specimens sold separately on page 5 of the Ginsberg catalog. Made of stainless steel or chrome, these tools give students and teachers greater cutting ease, slicing through delicate and tough tissues alike.

The sturdy handles provide a firm grip. NEEDLES Perfect for delicate dissection, separating and manipulating tissue without tearing, these dissection needles come in different styles for various applications. Specialized for different dissection purposes, the chrome or stainless steel forceps are long lasting and simple to clean.

Pins serve as a guide in dissection, while a bent tip allows students a good view of what they are doing. Special cartilage forceps permit heavy-duty handling and gripping. Two metals, 2 lengths, and 2 tips give your students a good selection of scissors to use for their job. These various highquality tools are designed for more specialized jobs. We have the rest! A variety of specimens consisting of some members of the kingdom Animalia.

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A glass jar and lid are also included. No sharp edges or little pins to lose. Students collect and mount their treasures from nature on the soft batting. If they get dirty, submerse in water to clean. Hang tab is included in the size. All Grades. They are reusable, long-lasting, and ideal for displaying most organisms of the class Insecta. They can be used in a variety of ways in a scientific environment.

Examples include: a coverslip placed over a specimen to give direct measurements with microscopes, an eyepiece reticle in a microscope — just cut to the diameter required to fit the eyepiece — guide circles are included, a stage micrometer — to calibrate a microscope, a specimen support — place the specimen directly on the film reticle, or a direct reading scale for magnifiers. This small rugged scope allows quick viewing of 3-D specimens. It is a perfect microscope for lab or field use.

Some special features for young scientists include: sturdy construction of cast metal, no knobs to break or lose, and a chemical-resistant finish. The microscope also incorporates a built-in light-gathering prism for simple lighting and a sliding barrel focus adjustment which prevents accidental impact with slides. It comes with spring stage clips, a 10x eyepiece and a 4x objective lens for good quality viewing.

The triple nosepiece features 4x, 10x, 40x objectives. This scope also has low-position coarse focusing with a built in slip clutch to prevent gear damage. The built in V illumination is great for viewing all types of specimens. The protective case is included. Requires 2 "AA" batteries which are not included.

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The plastic slides are packed in a plastic box for safe keeping. It is so inexpensive, each student can have their own. With a 2. The grid system incorporated into the 5 cm square bottom opening can be used as a gauge to compare size and proportions. Each slide is clearly identified. The slides are packed in a plastic storage box with slits for organization and safe storage. As the "lung" fills with air, through relaxation and contraction of the diaphragm muscle, students visualize how our lungs work.

A sturdy rubber sheet replicates the diaphragm. As the rubber sheet is pulled downward, the pressure within the chamber causes the "lung" to expand and take in air. When released, the "lung" will deflate. Two balloons attached to a Y-tube simulate the lungs. The chest cavity is represented by a half-gallon plastic bell jar with an open top and stout rubber sheet which acts as a diaphragm.

As the diaphragm is pulled downward, the atmospheric pressure is lowered inside the chamber causing the lungs to expand, taking in air. When the diaphragm is released, the lungs deflate. Includes lesson plan. The kit includes a transparent plastic container, Y-tube "trachea", balloon "lungs", rugged rubber sheet "diaphragm" and the necessary hardware and instruction sheet. The double thistle tube with a porous membrane is held upright with the membrane covered end in a jar of water. When a sugar solution is added at the top of the tube, the liquid will rise in the tube. Included are: a battery jar, thistle tube with membrane, and a stable support.

A well written instruction sheet will guide you through the 2 suggested experiments. It measures blood pressure with a hook and loop closure arm cuff and an easy to read dial. It comes with its own vinyl storage case. Bulb made of PVC. Use these in combination with our Aneroid Sphygmomanometer, , while working with blood pressure. This economical stethoscope is light and adjustable with a sensitive chest piece. Ideal for many basic diagnostic uses. The durable arm cuff closes with hook and loop and has a large easy to read gauge.

The Stethoscope is light weight and adjustable with a highly sensitive chest piece for easy listening. Ideal for basic diagnostic uses. Vinyl storage case included. It helps students understand the relationship between the human body and its skeleton. It can also be used for studying the morphology of bones and construction of joints. The skeleton is of an adult male in a standing posture. The joints of the upper and lower extremities are movable.

The spinal column shows the spinal cord, nerve exit, vertebral arteries, and a herniated disc. It is constructed of rugged plastic with a heavy metal base for an extra measure of stability. Included is a detailed key. The model features nerve roots, spinal cord, the vertebral artery, cartilage highlighted in green, and a herniated disk. A detailed key is included. The life-sized model features a spring mounted mandible, a detachable skull, and three removable teeth.

Show all of the major systems: respiratory, circulatory, digestive, nervous and urinary systems; also feature the musculature system. The lungs, heart, liver, stomach and intestines are removable for further examination. A detailed colored key is included for reference. Focusing on all major parts of the brain, students will become familiar with how the brain looks as well as how it functions. The model is made of plastic and comes with a base. A detailed key is provided. Right internal jugular vein Right external jugular vein Right subclavian artery Brachiocephalic vein Superior vena cava Pulmonary trunk Ascending aorta Aortic arch Right common carotid artery.

Left common carotid artery Left subclavian vein Right atrium Left atrium Right ventricle Apex of the heart Right coronary artery Left coronary artery Great cardiac vein. The model is made of heavy duty plastic placed on sturdy base. Detailed key included. Approximate size: 6" x 5" x 6", 2 lbs. Approximate size: 5. This model shows blood vessels, muscles, optical nerves, and other features of the human eye.

It rests on a sturdy base and can be dissected horizontally to expose the sclerotic, choroids, and retina. The cornea and iris are detachable. Approximate size: 7. Attributes to this model are the ability to dissect portions of the ear into six parts. Portions that come apart are the tympanic membrane with the malleus, incus, and attached stapes.

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The petrous portion of the temporal bone, which reveals the middle and inner ear chambers, and the external ear is represented by the auricle and auditory canal. This model includes a sturdy base and is made out of strong plastic. Approximate size: It is the perfect tool for the instruction of brushing techniques and proper oral hygiene.

The back side of the model is printed with questions that are great for reviewing cell parts and building vocabulary. Includes a repair patch. No Latex! Additional Dithiolate Examples. New substances and composites including nanostructured materials are envisioned for innumerable areas including magnets for the communication and information sector of our economy. Hence, research groups worldwide are targeting the preparation and study of new magnets especially in combination with other technologically important properties, e.

In the past few years our understanding of magnetism and magnetic materials, thought to be mature, has enjoyed a renaissance as it is being expanded by contributions from many diverse areas of science and engineering. This important contribution to magnetism and more importantly to science in general will lead us into the next millennium. As this millennium begins the time is appropriate to pool our growing knowledge and assess many aspects of magnetism. This series entitled Magnetism: Molecules to Mate- XII rials provides a forum for comprehensive yet critical reviews on many aspects of magnetism that are on the forefront of science today.

Schweitzer Pessac France Joel S. Several of these materials show remarkable features and have made a significant contribution to the development of molecular materials science. It is worth mentioning some examples of the molecular materials based on metalbis 1,2-dichalcogenate anionic complexes based that have made a significant contribution to the field of molecular material science, in the last decades. Since then among the strategies followed to obtain cooperative magnetic properties, considerable attention has been given to the linear-chain electron-transfer salts based on metallocenium donors and on planar acceptors.

An extensive study of these salts was made, covering a variety of aspects including the structure-magnetic property relationship [10], and the effects of spin variation and of spinless defects [10]. Furthermore they provided a valuable basis to test the various models that were proposed in order to explain the magnetic coupling and magnetic ordering in the molecule-based magnets [14, 15]. The work with ET salts based on metallocenium donors and on planar metal bisdichalcogenate radical anions is summarized in this chapter.

Most of the materials studied to date are decamethylmetallocenium based ET salts, other compounds based on different metallocenium derivatives have also been reported and will be 1. The metal bis-dichalcogenate complexes mentioned in this chapter are represented in Scheme 1. As magnetic ordering is a bulk property, particular attention will be given to the supramolecular arrangements which determine the magnetic behavior. The crystal structure of the compounds will be correlated with the magnetic behavior of these ET salts.

The magnetic coupling in the ET salts based on decamethylmetallocenium donors has been analyzed mainly through McConnell I [18] or McConnell II [19] mechanisms, and this issue is still a subject of controversy [15, 20]. Of these models, McConnell I has been most often used in the interpretation of the magnetic behavior of these salts, as, in spite of its simplicity, it has shown good agreement with the experimental observations.

In this chapter the interpretation of the magnetic coupling will be analyzed in the perspective of this model. However, it should be mentioned that the validity of the McConnell I mechanism has been questioned both theoretically [21] and experimentally [22]. In these salts four distinct types of linear chain arrangements have been observed and are represented schematically in Figure 1. For most of the ET salts based on types I and III arrangements neutral chains , only one type of chain arrangement was observed. However, in the case of compounds based on types II and IV arrangements charged chains , more complex crystal structures could be observed, resulting from the required charge neutralization.

Table 1. Representation of the basic types of mixed chain sequences observed in the ET salts based on metallocene donors and on metal bis-dichalcogenate acceptors. Unit cell parameters and chain type for the mixed chain salts. While in the case of the cyano radical based salts, most of the observed structures present a type I structural arrangement, in the case of the ET salts based on metal bis-dichalcogenate acceptors a much larger variety of arrangements was observed, as described above.

The unit cell parameters of the ferrocenium derivative salts with crystal structures based on segregated acceptor stacks are shown in Table 1. Unit cell parameters for the segregated stack salts. In Figure 1. Magnetic characterization of type I ET salts. While for measurements with the applied field perpendicular to the chains, no transition was observed and a linear field dependence was observed for the magnetization, as expected for an AFM. The nature of the intra and interchain magnetic interaction is in good agreement with the predictions of the McConnell I mechanism [26].

In this case the interchain interactions must be particularly large as they seem to be the dominant interactions Fig. Hydrogen atoms were omitted for clarity. In this compound, no intrachain DA short contacts were found and the closest interatomic separation between the acceptor and the Cp ring corresponds to Ni—C contacts of 4.

In this salt the most relevant interchain contacts concern the out-of registry pairs I—II and I—IV, these arrangements are similar and the first one is shown in Figure 1. These pairs show interchain DA C—S contacts, involving C atoms of the Me groups of the donors and S atoms of the acceptors, with a separation of 3. This behavior is attributed to the coexistence of FM intrachain interactions with interchain AFM interactions. A view normal to the chains is shown in Figure 1. For this series of compounds the shortest interchain interionic separation was found in the in-registry pair I—II, shown in Figure 1.

In the other interchain arrangements the interchain contacts are considerably larger and the closest separations occur for the I—IV pair Figure 1. The inset shows the magnetization temperature dependence at 1, 2, 4 and 8 kG. The magnetization field dependence at 1. The critical field temperature dependence obtained from the isothermal closed symbols and isofield open symbols measurements is shown in Figure 1. The intrachain DA contacts along c and the interchain AA Se—Se or S—S contacts along a are expected to give rise to quasi-2D magnetic systems ac plane , as the other interchain contacts are expected to give rise to much weaker magnetic interactions.

Below TN , two field induced transitions were observed to occur, and at 1. The analysis of the crystal structures, the magnetic behavior and atomic spin density calculations of several ET salts based on decamethylferrocenium and on metal-bis dichalcogenate acceptors with structures consisting of arrangements of parallel alternating DA linear chains, allowed a systematic study of the intra and interchain magnetic interactions [26].

In the case of these compounds a spin polarization is observed in the metallocenium donors but not in the acceptors described so far. The analysis of the intrachain contacts in the perspective of the McConnell I mechanism suggests the existence of intrachain FM coupling, through the contacts involving the metal or chalcogen atoms positive spin density from the acceptors and the C atoms negative spin density from the Cp ring of the donors, which shows good agreement with the experimental observations.

A strict application of the McConnell I model was not possible in the case of the interchain contacts, as the shortest contacts would involve mediation through H or F atoms, which are expected to present a very small spin density [26]. However the results regarding the nature of the interchain magnetic coupling would be compatible with that model if the contacts involving H or F atoms were neglected, as all the atoms involved in these contacts present a posi- 1. This study revealed that metamagnetism, which was observed in several compounds presenting a crystal structure consisting of a parallel arrangement of alternated 1D chains, is expected to occur in other compounds presenting a similar solid state structure, in the case of the metal bis-dichalcogenate acceptors no spin polarization effect is found.

As in the other salts described above, the crystal structure consists also of a parallel arrangement of the chains. For the I—IV pair arrangement, shown in Figure 1. The intrachain interactions are expected to be AFM. As in the previous compounds exhibiting this type of structure metamagnetic behavior is also expected to occur at low temperatures. A projection of the crystal structure along the stacking direction, [], is shown in Figure 1. Short interatomic DA intrachain distances were observed, involving one C from the Cp and a S atom from the acceptor, with a C—S distance of 3.

A projection of the crystal structure along a is shown in Figure 1. In the acceptor layers, relatively short interionic AA distances were found, involving S atoms from the central NiS4 fragment and a C atom from the thiophenic fragment of the ligand, as shown Figure 1. These contacts give rise to a set of layers bc layers composed of parallel alternated DADA chains, as shown in Figure 1.

Two chains from adjacent layers are shown in Figure 1. The chains in the bc layers present an out-of registry arrangement. The contacts between the chain in adjacent layers correspond to the S—C AA contacts previously mentioned in the case of the acceptor ab layers. However the closest contact involves the same C in both compounds.

The temperature dependence of HC is shown in Figure 1. The poor quality of the crystals of this compound has so far prevented crystal structure determination, however a crystal structure similar to that observed for the Fe and Cr analogues, is expected for this compound. From the room temperature crystal structure analysis the stronger interionic contact is expected to be AFM as it corresponds to the intrachain DA contact involving two atoms with negative spin densities, a S from the thiophenic ring of the acceptor and a C from the C5 ring of the donor.

The shorter AA contacts from the anionic layers are expected to give rise to FM interactions, as the spin densities of the atoms do not have the same sign. This change can be attributed to small variations in the interionic contacts on cooling. In both intrachain DA and interlayer AA arrangements, besides the shorter contacts referred to before, there are also slightly longer interionic separations, which could lead to different types of interactions for both the DA and AA contacts.

The experimental results indicate that in this case the FM interactions dominate the magnetic behavior of this compound. A view of the crystal structure along the type II chain direction, [], is shown in Figure 1. In the type II chain layers the acceptors are strongly dimerized with a Pt—Pt distance of 3. Apart from the AA contacts no other short contacts were observed in these layers.

The DDA layer presents a unique arrangement, where the donors sit on top of the extremity of the acceptors, these DDA units form edge to edge chains, as shown in Figure 1.

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In these layers the closest interionic separations involve one C from the Cp and a S atom from the acceptor, with a C—S distance of 3. T plot in Ref. A view of the structure along the chain direction is shown in Figure 1. The intrachain DA separation is considerably larger and the shorter contacts between the acceptor and the Cp rings correspond to a S—C contact S from the C2 S2 C fragment with distances of 3. Several short AA S—S interchain contacts were observed in this compound and the crystal structure can be better described as being based on layers of out-of-registry parallel chains, one of these layers is shown in Figure 1.

The intralayer interchain contacts are Fig. This can be attributed to a change in the dominant magnetic interactions, due to structural changes on cooling. This is the first and only case, to date, in this class of compounds to present FM ordering and this behavior was analyzed in the light of the McConnell I mechanism, namely for the intradimer magnetic interactions due to a spin polarization effect in the acceptor molecules.

The solid line corresponds to the Brillouin function considering the donor and acceptor spins, while the dashed line corresponds only to the contribution from the donor molecules. For this compound the magnetization isothermals circles in Figure 1. It is worth mentioning that, in the case of the interchain intralayer interactions, the shorter contacts involving two S atoms from the central MS4 fragment are expected to be AFM, while the weaker contacts involving a S from the central MS4 fragment and one of the S from the C2 S2 C fragment are predicted to give rise to FM interactions.

In this case a slight change in the interionic arrangement could change the nature of the intralayer magnetic interactions. Short intralayer contacts, similar to those observed in the previous compound, were ob- 28 1 Metallocenium Salts of Radical Anion Bis Dichalcogenate Metalates served, with a S—S distance of 3. The magnetic behavior is clearly dominated by the AFM intradimer interactions. In this salt the acceptors are strongly dimerized through Ni—Se bonds, the Ni dsit 2 units are slipped see Figure 1. At low temperatures, the magnetic field dependence follows the predicted values for the isolated donors, as in the case of the analogous compounds presenting dominant AFM interactions, described previously.

The supramolecular arrangement in the type III chain based salts, at high temperatures, is consistent with the existence of dominant AFM interactions through AA interactions. For the compounds with dominant FM interactions at low temperatures, the magnetic behavior can be related to the distinct dimer arrangements. The dimer arrangements along with the dimer overlap are illustrated in Figure 1. These charged layers are separated by acceptor layers, as represented in the view along [] in Figure 1. The chains are regular and the Cp fragments of the donor sit above the dmio ligands of the acceptor, as shown in Figure 1.

The closest interionic intrachain DA separation involves a S atom from the central Fig. The chains in the layers are quite isolated and the solvent molecules are located in cavities between the DDA chains layers and the anionic layers, as shown in the view of the structure in Figure 1. Short contacts were observed in the anionic layers involving S atoms from the five-membered C2 S2 C ring of the dmio ligands, with a S—S distance of 3. The observed magnetic behavior is attributed to the intrachain interactions, as the contacts in the anionic layers are expected to give rise to AFM interactions since the spin density of the atoms involved in these contacts have the same sign.

The DDA chains are relatively isolated and the solvent is located in cavities between the chains. The magnetic behavior of this compound is dominated by FM interactions [17], which are attributed to the observed DA intrachain contacts. A view along the chain direction, [], is shown in Figure 1.

The shorter DA intrachain separations involve S atoms from the acceptors and C atoms from the Cp rings of the donors aligned with the chain direction presenting S—C distances of 3. The chains in the same layer are relatively isolated, but short distances between the chains and anions on the anionic layers were observed. As shown in Figure 1. AA contacts were observed involving C atoms from the terminal C6 ring of the ligands and Ni atoms from the acceptors in the anionic layer, with a C—Ni distance of 4.

DA contacts were also observed involving one of the C atoms from the Cp ring of the donor perpendicular to the chain axis and one of the C atoms from the C6 ring of the acceptor, with a C—C distance of 3.

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  6. Short contacts were also observed in the anionic layers, as shown in Figure 1. The magnetization field dependence, at 1. In this compound both donors, from the DD pair in the repeat unit, are perpendicular to the chain direction, as shown in Figure 1. Short intrachain contacts were observed and involve the Cu from the acceptor and a C from one of the Me groups in the donor, with a Cu—C distance of 3. The side-by side donors are relatively close and C—C distances of 3.

    No short interionic intrachain contacts were observed and the chains are essentially isolated. C—C DD , observed in the crystal structure, as the spin density is expected to be of the same sign in the atoms involved in the contacts. In the case of this compound the magnetic behavior is dominated by intradimer antiferromagnetic interactions. As most of the work with this type of ET salts was essentially motivated by the results obtained with the salts based on decamethylmetalocenium donors and polynitrile planar acceptors, the use of different metallocenium derivatives was limited to a small number of compounds.

    The work developed with salts of other metallocenium derivative donors, including also diamagnetic donors, was also motivated by the observation of ferromagnetic ordering in NH4 [Ni mnt 2 ]H2 O [7], as the magnetic ordering in this compound is only due to the acceptors. At room temperature, the crystal structure of this salt consists of regular stacks of eclipsed acceptors and the magnetic behavior of NH4 [Ni mnt 2 ]H2 O is dominated by AFM interactions down to ca. The magnetic behavior of these compounds is dominated by AFM interactions between the acceptor units in the dimers.

    The crystal structures all molecular and crystal structure representations were performed using SCHAKAL [50] of these salts were correlated with the magnetic properties, and the magnetic coupling was analyzed in the perspective of the McConnell I mechanism. The use of the planar metal bis-dichalcogenate acceptors in the preparation of new molecule-based materials followed the report of bulk ferromagnetism in decamethylmetallocenium-based ET salts with small polynitrile acceptors such as TCNE and TCNQ.

    One of the goals related to the use of the metal bisdichalcogenate acceptors is to obtain an increase in the dimensionality in relation to polynitrile-based ET salts and, as a consequence, to obtain new materials with interesting cooperative magnetic properties. These salts exhibit a large variety of magnetic behavior. Different types of magnetic ordering were observed at low temperatures. In these compounds the relative orientation of the donor pairs depends on the acceptors.

    In spite of the simplicity of McConnell I model, it has shown to be quite effective in the interpretation of the magnetic behavior in the ET salts based on metallocenium radical donors and on planar metal bis-dichalcogenate radical anions. However in the compounds presenting complex structures with possible competition between FM and AFM intermolecular contacts, e.

    The study of these type of ET salts, which began in the late 80s, has gained renewed interest in recent years and a large number of compounds are still under study. Besides the significant number of compounds presenting metamagnetism, the use of acceptors showing spin polarization, leads to salts presenting other types of ordering, such as ferro and ferrimagnetism. The use of these types of acceptors seems quite promising for the preparation of new molecule-based materials. Acknowledgments The authors wish to thank their co-workers, in particular D. Belo, S. Meira, I.

    Santos, J. Novoa and R. References 39 References 1. Kobayashi, H. Nalwa, John Wiley, Chichester, , Vol. Kim, Y. Sasaki et al. Bray, H. Hart, Jr. Interrante et al. Almeida, R. Rovira, J. Veciana, E. Ribera et al. Sutter, M. Fettouhi, C. Michaut et al. Allan, A. Coomber, I. Marsden et al. Miller, J. Callabrese, H. Rommelmann et al.

    Chittipedi, K. Cromack, J. Miller et al. Miller, A. Epstein, in Research Frontiers in Magnetochemistry, ed. Epstein, in E. Coronado, P. Gatteschi, J. Miller ed. Coranado, P. Yee, J. Manriquez, D. Dixon et al. Eichhorn, D. Skee, W. Broderick et al. Miller, R. McLean, C. Vasquez et al. Broderick, D. Eichhorn, X. Liu et al. Broderick, J. Thompson, E. Day et al. Broderick, B. Hoffman, J. Epstein, Angew. Calabrese, A. Epstein, Inorg. Thompson, M. Godfrey et al. McConnell, J. McConnell, Proc. Robert A. Welch Found. Deumal, J. Novoa, M. Bearpark et al.

    Phys, Chem. A , , Cirujeda, J. Veciana et al. Gama, D. Thompson, B. Hoffman, Inorg. Miller, personal communication. Meira, L. Pereira et al. Meira, V. Gama et al. Fettouhi, L. Ouahab, M. Hagiwara et al. Duarte, V. Gama, manuscript in preparation. Ouahab, E. Codjovi et al. Belo, H. Alves et al. References D. Alves, S. Belo, J. Meira et al. Gramlich, D. Arx, A. Togni, Inorg. Alvarez, R. Vicente, R. Hoffmann, J. Sano, H. Adachi, H. Yamatera, Bull.

    Day, J. Qin, C. Yang, Acta Crystallogr. C , 54, Hobi, S. Gramlich et al. Pullen, C. Faulmann, K. Pokhodnya et al. Qi, Y. Xiao-Zeng, C. Jin-Hua et al. C , 49, Faulmann, F. Delpech, I. Malfant et al. Gama, S. Ramos et al. Belo et al. Faulmann, A. Pullen, E. Belo, I. Santos et al. Cotton, Interscience, New York, , p. The physical characteristics of current interest involve optical properties, particularly with respect to natural optical activity. In the case of a magnet with non-centrosymmetric structure, the space-inversion and time-reversal symmetry are simultaneously broken.

    Moreover, when a magnet is characterized by chiral structure, the magnetic structure of the crystal is expected to be a chiral spin structure. These magnets display not only asymmetric magnetic anisotropy but also various types of magneto-optical phenomena such as the non-linear magneto-optical effect and magneto-chiral dichroism [9—11]. Materials in this category are not only of scientific interest, but also afford the possibility for use in new devices. To obtain non-centrosymmetric and chiral molecule-based magnets, the geometric symmetry such as chirality must be controlled in the molecular structure as well as in the entire crystal structure.

    In this chapter we describe recent results regarding the construction, structure and magnetic and optical properties of molecule-based magnets with non-centrosymmetric and chiral structures. The investigation of the properties and the search for magnetic materials that contain ferroelectric order are subjects of increasing interest [11, 12]. These multiferroic materials possess specific properties due to the com- 42 2 Chiral Molecule-Based Magnets bined effect of ferromagnetic nature and ferroelectric nature in the same phase.

    The generation of an electric dipole asymmetric field in the crystal is readily achieved by introduction of chirality or non-centrosymmetric structure. These classes of materials are not identical to ferroelectric materials; however, they exhibit an electric dipole asymmetric field in the crystal or material.

    They are expected to possess unique magnetic anisotropy, field induced second harmonic generation and the magneto-chiral optical effect due to the electric dipole asymmetric field. On the basis of i , the spins experience an asymmetric magnetic dipole field. The asymmetric magnetic dipole moments operate the spins aligned asymmetrically through spin—orbital interaction. In order to facilitate matters, we assume that the spins are sited on a helix and the ferro- or ferrimagnetic interaction occurs between nearest neighbor spins.

    In this case, the spins are aligned in helical or conical spin alignment by an asymmetric magnetic dipole field and ferromagnetic interaction. Figure 2. Expected magnetic structure for chiral magnets. Over the last 15 years, the nonlinear magneto-optical phenomena have been intensively studied [14—22] and magnetization-induced second harmonic generation MSHG has received special attention due to its large magnetic effects, e. In the electric dipole approximation, second harmonic generation SHG is allowed in media with broken inversion symmetry [23]. Most magnetic materials are, however, centrosymmetric and, hence, the MSHG are mainly reported from the surface of magnetic materials [15, 16].

    MSHG observations from the bulk crystals are limited. The MSHG effect is useful for the topography of magnetic domains [24]. Furthermore, applying a magnetic field can control the MSHG signal [20—22]. Hence, an attractive method for studying nonlinear optics is to prepare ferromagnetic materials, which display SH activity. Chiral magnets are advantageous when compared to conventional metal or metal oxide magnetic materials because the space-inversion and time-reversal symmetry are simultaneously broken. EEE, 2. When E is sufficiently weak, Eq. In contrast, as E increases, the second optical response of the second term dominates Eq.

    Next the susceptibilities of magnetic substances will be examined. In Eq. The non-vanishing elements in each tensor are determined by space-time symmetry operations. In ferromagnetic substances, which have noncentrosynmetric structures, the simultaneous breaking of space and time-reversal symmetry leads to the coexistence of crystallographic and magnetization-induced electric-dipole contributions to the nonlinear optical susceptibility. These magnetic terms lead to magneto-optical effects in SHG. However, if one or both of them are complex, then interference is allowed and leads to effects, which are linear to the magnetization.

    Transmitted SH light is detected by a photomultiplier through color filters and a monochromator. Polarization combinations between the incident and SH radiation are adjusted using a babinet-soleil compensator and a pair of polarizers. A cryostat controls the temperature of the samples. The magnetic field is applied along the direction of light propagation using the electromagnet coil of a magneto-optical meter. Schematic illustration of the SHG measurement system.

    The magnetic field was applied along the light propagation direction using an electromagnetic coil. In contrast, strain-induced Bi:YIG has a noncentrosymmetric structure. In a Bi:YIG film, the distortion of the crystal structure breaks the space-inversion symmetry, which is evident in the SHG [29] and linear magnetoelectric effects.

    The crystal structure is in a non-centrosymmetric point group, 3m C3v , and has a threefold axis along the normal of the film. This equation shows that SHG is allowed at normal and oblique incidences. Pisarev et al. This equation can predict the angle dependence of I and is shown in Figure 2. In fact, Pisarev et al. In , Pavlov et al. In addition, A, B, and C are combinations of real and imaginary magn 1. The experimental data is consistent with the tensor analysis prediction.

    Thus, applying an 2. Predicted angle dependence of SH intensity a and rotational anisotropy b of the SHG intensity on film, based on Eq. Thin solid, thick solid, and dotted lines are zero, positive, and negative external magnetic fields, respectively. XX denotes the input-output polarization combinations.

    A, B, and C are obtained by fitting the data to Eq. The crystallographic contribution decreases linearly with temperature, but the magnetization-related contributions vanish at Tc. The observed temperature variations of crystallographic, magnetization-induced, and interference terms in the SHG intensity for the film. Reproduced with permission from Ref. Section 2. This effect is a combined effect of the natural optical activity of chiral material and the Faraday effect of the magnet Figure 2.

    This MChD effect involves the absorption coefficient of materials, which is dependent upon the direction of magnetization and light. Schematic illustration of a natural optical activity, b Faraday effect, and c magneto-chiral dichroism. It is important to generate fully chiral molecule-based magnets which are expected to exhibit a strong MChD effect. II, Chapter 2 , one-dimensional complexes exclusively form isotactic polymeric chains. In these complexes, two tert-butylaminoxyl groups are rotated out of the phenylene ring plane in a conrotatory manner; each molecule in the crystal has no symmetry element and is, therefore, chiral, i.

    Consequently, the 1-D polymeric chains are isotactic as all units are of the same chirality. The crystal lattice as a whole is achiral due to the presence of enantiomeric chains. When chiral organic radicals are employed in lieu of achiral biradicals, the chiral substituent group will induce chirality in the main one-dimensional chain. The molecular structures of these complexes are depicted in Figure 2. The MnII ion exists in an octahedral coordination environment with four oxygen atoms of two hfac anions and two oxygen atoms of different radical molecules in both crystals.

    As a result, the MnII ion and the chiral radical 1 or 2 form a one-dimensional structure. In this complex, two tert-butylaminoxyl groups are rotated out of the phenylene ring plane in a conrotatory manner; all molecules in the crystal display S axis chirality. Since no inversion centers are present in this space group, the chains are isotactic as all units and the crystal lattice as a whole, are chiral. Due to the use of the chiral ligand, the complex crystallized in a chiral space group, therefore, no chirality of the Mn II exists in this crystal.