16 1-15 magmater-2 (1)

04/18/2023BITSPilani, Pilani Campus

CHEM F343: Inorganic Chemistry III

BITS PilaniPilani Campus

Dr. Inamur R. Laskar

Course Description

• Course Description: Inorganic elements in biological systems: role of

alkali and alkaline earth metal ions, iron, copper and molybdenum; metalloenzymes. Metals in medicine: metal deficiency and disease; toxicity of mercury, cadmium, lead, beryllium, selenium and arsenic; metals used in diagnosis and chemotherapy; electronic, magnetic and optical materials; some emerging research topics in inorganic chemistry



Text Books:

T1: Inorganic Biochemistry An Introduction, J. A. Cowan, Wiley-VCH, 2nd edition.

T2: The Science and Engineering of Materials, Donald R. Askeland, Pradeep P. Phule, Cengage learning (Indian edition)



Reference Books:

R1. S. J. Lippard and J. M. Berg, "Principles of Bioinorganic Chemistry", University Science Books

R2. I. Bertini, H. B. Gray, S. J. Lippard, J. S. Valentine, Bioinorganic Chemistry”, Viva, 1998.

R3. William D. Callister, Materials Science and Engineering, Wiley-India Edition, 2007.

ContentsLec. No.

Topics to be covered Learning ObjectivesReference:

1 Bioinorganic Chemistry Introduction Class note

2-4 Metal ion Storage and Transport Metal ion uptake and transmembrane ion transport, storage of metal ions

T1; p133-61

5-7 Metalloproteins and Metalloenzymes

Oxygen carriers and Hydrolase enzymes T1; p167-194


Redox Chemistry of transition metal ions in biology

T1; p203-221 and Class note


Redox Chemistry: Electron transfer pathways

T1; p221-247 and Class note

14-16 Role of alkali and alkaline earth metal ions

Membrane translocation, ion pumps, complexes with nucleic acids

T1; p257-284

17-19 Choice, uptake and assembly of metal containing units in biological system

Enrichment strategies and intracellular chemistry of low-abundant metals, Spontaneous self-assembly of metal clusters

Class note

20 Tungstoenzymes Biochemical properties of tungstoenzymes, Structural properties of tungstoenzymes

Class note

21 Metal Deficiency and Disease Introduction and overview, Essential metals, Anemia and Iron, Causes and consequences of zinc deficiency, copper deficiency

Class note

22 Toxic effects of Metals Copper overload and Wilkinson diseases, Iron Toxicity, Toxic effects of other essential elements, Mercury Toxicity and Bacterial resistance, cadmium and lead toxicity

Class note

Contents23 Metals used in diagnosis

and chemotherapyRadiodiagnostic agents, Magnetic Resonance Imaging, Lithium and mental health, Gold and Rheumatoid Arthritis

Class note

24-27 Electronic Materials Band structure of solids, Conductivity in solids, Superconductivity, Semiconductors, Insulators and dielectric properties, Piezoelectricity, Pyroelectrocity, Ferroelectrocity

T2; p677-718

28-32 Magnetic Materials Classification of magnetic materials, Magnetization, Permeability, Diamagnetic , Paramagnetic, Ferromagnetic, Superparamagnetic materials, Domain structure and the hysteresis loop, The curie temperature, Metallic and ceramic magnetic materials

T2; p725-751

33-36 Photonic Materials The electromagnetic spectrum, Refraction, Reflection, Absorption and Transmission, Selective absorption, Transmission or Reflection, Example and use of emission phenomena

T2; p757-781

37-40 Emerging areas in inorganic chemistry

Nanomaterials, supramolecular chemistry etc

Class note



Bioinorganic Chemistry 20 Lectures

Metal ions in medicine 4 Lectures

Materials: Electronic, Magnetic, Photonic 13 Lectures

Emerging areas in inorganic chemistry 3 Lectures


EvaluationComponent.

Duration Weightage Nature of Component.

Mid Sem Test 1.5h 30% Close Book

Tutorial Tests ------- 30% Continuous

Compre.Exam.

3h 40% Close/Open Book


Magnetic Materials

Have you ever wondered?• What materials are used to make audio and video

cassettes?• What affects the lifting strength of a magnet?• What are soft and hard magnetic materials?• Are there nonmagnetic materials?• Could there be materials that develop mechanical

strain upon the application of a magnetic field?

Examples in terms of Application of Magnetic Materials

• Magnetic materials are used to operate such things as electrical motors, generators and transformers.

• Much of the data storage technology (computer hard disks, computer disks, video and audio cassettes etc.) is based on magnetic particles

• Magnetic materials are also used in loudspeakers, telephones, CD players, TV and video recorders

• Super conductors can also be viewed as magnetic materials.• Magnetic materials such as iron oxide (Fe3O4) particles, are used

to make exotic compositions of liquid magnets or ferrofluids.• The same iron oxide particles are used to bind DNA molecules,

cells and proteins

Classification of Magnetic Materials: Any non magnetic materials?

• Strictly speaking, there is no such thing as a “nonmagnetic” material.

• Every material in this world consists of atoms; atoms consists of electrons spinning around them; similar to a current carrying loop that generates a magnetic field.

• Thus every materials responds to a magnetic field.• The manner in which this response of electrons

and atoms in a material is scaled and that determines whether a material will be strongly or weakly magnetic.

Classification of Magnetic Materials: Ferromagnetic/Ferrimagnetic/Nonmagnetic

• Examples of ferromagnetic materials are materials such as Fe, Ni, Co and some of their alloys. Examples of ferrimagnetic materials include many ceramic materials such as nickel zinc ferrite and manganese zinc ferrite.

• The term so called nonmagnetic usually means that the materials is neither ferromagnetic nor ferrimagnetic.

• These nonmagnetic materials are further classified as diamagnetic (e.g., superconductors) or paramagnetic.

• In some cases, we also encounter materials that are antiferromagnetic or superparamagnetic.

Classification of Magnetic Materials: Soft and Hard Materials

• Ferromagnetic materials are further classified as soft and hard materials.

• High purity iron or plain carbon steels are examples of a magnetically soft materials as they can become magnetized, but when the magnetizing source is removed, these materials lose their magnet-like behavior.

• Permanent magnets or hard magnetic materials retain their magnetization. Many ceramic ferrites are used to make inexpensive refrigerator magnets. A hard magnetic material does not lose its magnetic behavior easily

Magnetic Dipoles and Magnetic Moments : Origin of Magnetic Dipoles

• The magnetic behavior of materials can be traced to the structure of atoms. Electrons in atoms have a planetary motion in that they go around the nucleus.

• The orbital motion of the electron around the nucleus and the spin of the e about its own axis cause separate magnetic moments.

• These two moments (e.g., spin and orbital) contribute to the magnetic behavior of materials.

• The magnetic moment of an e due to its spin is known as Bohr magneton (B). This is the fundamental constant and is defined as:

B = Bohr Magneton = qh/4me = 9.274 x 10-24 Am2

q=charge of the e; me = mass of the e

Magnetic Dipoles and Magnetic Moments : Contribution of nuclear magnetic moment

• The nucleus of the atom consists of protons and neutrons.

• These also have a spin.• However, the overall magnetic moment due to

their spin is much smaller than that for es.• We normally don’t encounter the effects of a

magnetic moment of a nucleus with the exception of such applications as nuclear magnetic moments.

Magnetic Dipoles and Magnetic Moments : The world would be magnetic place!

• We can view the es in materials as small elementary magnets.

• If the magnetic moments due to es in materials could line up in the same direction, the world would be a magnetic place.

• However, this is not the case.• Thus, there must be some mechanism by which the

magnetic moments associated with e spin and their orbital motion get canceled in most materials, leaving behind only a few materials that are magnetic

• There are the two effects that, fortunately make most materials in the world not be magnetic

Magnetic Dipoles and Magnetic Moments : Why the world are not magnetic-two effects

• First, we must consider the magnetic moment of atoms• According to the Pauli Exclusion principle, two es within the

same energy level (orbital state) must have opposite spins.• This means their e-derived magnetic moments are opposite

and cancel out.• The second effect is that, the orbital moments of es also

cancel each other. • Thus, in a completely filled shell, all electron-spin and orbital

moments will cancel out. This is why atoms of most elements do not have a net magnetic moment. Some elements, such as transition elements (3d, 4d, 5d partically filled), the lanthanides (4f partially filled) and actinides (5f partially filled) have a net magnetic moment since some of their levels have unpaired e.

Magnetic Dipoles and Magnetic Moments : 3d Transition Metals

• Transition metals have an inner energy level that is not completely filled.

• Except for Cr and Cu the valence es in the 4s level are paired; the unpaired es in Cr and Cu are canceled with other atoms

• Cu has a completely filled 3d shell and this does not display a net magnetic moment

• The es in the 3d level of the remaining transition elements do not enter the shells in pairs. Instead, as in Mn, the first five es have the same spin. Only after half of the 3d level is filled do pair with opposite spins form. Therefore, each atom in a transition metal has a permanent magnetic moment, which is related to the number of unpaired es. Each atom behaves a net magnetic moment.

Magnetic Dipoles and Magnetic Moments : 3d Transition Metals

• In many elements, these magnetic moments exist for free individual atoms, however when the atoms form crystalline materials, these moments are quenched or canceled out.

• Thus, a number of materials made from elements whose atoms have a net magnetic moment of 4B ( 4times the magnetic moments of an e), however FeCl2 crystals are not magnetic

Magnetic Dipoles and Magnetic Moments : 3d transition elements response to the applied

field• The response of the atom to an applied magnetic field depends on how the magnetic

dipoles represented by each atom react to the field. Most of the transition elements (e.g., Cu, Ti) react in such a way that the sum of the individual atoms’ magnetic moments is zero.

• However, the atoms in nickel, iron and cobalt undergo an exchange interaction, whereby the orientation of the dipole in one atom influences the surrounding atoms to have the same dipole orientation, producing a desirable amplification of the effect of the magnetic field.

• In the case of Fe, Ni and Co, the magnetic moments of the atoms line up in the same directions, these materials are known as ferromagnetic.

• In certain materials, such as BCC Cr, the magnetic moments of atoms at the center of the unit cell are opposite in direction to those of the atoms at the corners of the unit cell, thus, the moment is zero.

• Materials in which there is a complete cancellation of the magnetic moments of atoms or ions are known as anti-ferromagnetic.

• Materials in which magnetic moments of different atoms or ions do not completely cancel out are known as ferrimagnetic materials.

Relationship Between Magnetic Field and Magnetization: Flux density or Inductance

• Suppose a coil having n turns• When the electric field is passed through the coil, a magnetic field H

is produced, with the strength of the field is given by• H = nI/L (where n is the nuber of turns, L is the length of the coil (m)

and I is the current (A). The units of H is therefore ampere-turn/m or simply A/m. An alternate unit for magnetic field is oersted, obtained by multiplying A/m by 4π x 10-3

• When a magnetic field is applied in a vacuum, lines of magnetic flux are induced. The number of lines of flux, called the flux density or inductance B, is related to the applied field by, B = μ0H, where B is the inductance, H is the magnetic field and μ0 is the constant called the magnetic permeability of the vacuum

• If H is expressed in units of oersted, then B is in gauss and μ0 is gauss/oersted. In an alternate set of units, H is in A/m, B is in tesla (or weber/m2 ) and μ0 is 4π x 10-7 weber/A.m.

Relationship Between Magnetic Field and Magnetization: Relative Permeability

• When we place a material within the magnetic field, the magnetic flux density is determined by the manner in which induced and permanent magnetic dipoles interact with the field. The flux density now is, B = μH, where μ is the permeability of the material in the field.

• If the magnetic moments reinforce the applied field, then μ > μ0, greater number lines of flux that can accomplish work are created and the magnetic flux are magnified. If the magnetic moments oppose the field, then μ < μ0

• We can describe the influence of the magnetic material by the relative permeability μr where,

μr = μ/ μ0

Relationship Between Magnetic Field and Magnetization: Relative Permeability

• A large relative permeability means that the material amplifies the effect of the magnetic field. Thus, the relative permeability has the same importance that conductivity has in dielectrics.