Undergraduate
  1. General chemistry  1.1. Introduction to Chemistry  1.2. Atomic Structure  1.2.1. Subatomic particles  1.2.2. Atomic Model  1.2.3. Quantum numbers  1.2.4. Electron Configuration  1.2.5. Periodic trends  1.2.6. Isotopes and their applications  1.3. Chemical bond  1.3.1. Ionic bond  1.3.2. Covalent bonds  1.3.3. Metal Bond  1.3.4. Hybridization  1.3.5. Molecular geometry and VSEPR theory  1.3.6. Bond polarity and dipole moment  1.4. Stoichiometry  1.4.1. Mole concept  1.4.2. Empirical and molecular formula  1.4.3. Limiting reactant and excess reactant  1.4.4. Percent Yield and Purity  1.4.5. Dilution calculation  1.5. States of matter  1.5.1. Gas Laws  1.5.2. Matter and Intermolecular Forces  1.5.3. Solid and Crystal Structures  1.5.4. Phase diagram  1.5.5. Plasma and supercritical fluid  1.6. Chemical reactions  1.6.1. Types of Chemical Reactions  1.6.2. Balancing Chemical Equations  1.6.3. Thermochemical reactions  1.6.4. Reaction energy profiles  1.7. Solutions and Mixtures  1.7.1. Concentration units  1.7.2. Syndrome properties  1.7.3. Solubility and Solubility Rules  1.7.4. Henry's Law and Raoult's Law  1.7.5. Partition coefficient  1.8. Chemical equilibrium  1.8.1. Law of mass action  1.8.2. Le Chatelier's principle  1.8.3. Reaction quotient  1.8.4. To use this online calculator for Equilibrium Constant, enter Equilibrium Constant (Eq.) and hit the calculate button. Here is how the Equilibrium Constant calculation can be explained with given input values -> 0.05 = 0.05/0.  1.8.5. Acid-base balance  1.9. Acids and bases  1.9.1. Arrhenius, Brønsted–Lowry, and Lewis definitions  1.9.2. pH and pOH  1.9.3. Acid-base titration  1.9.4. Buffer Solution  1.9.5. Acid-base indicator  1.9.6. Polyprotic Acids and Bases  1.10. Electrochemistry  1.10.1. redox reactions  1.10.2. Galvanic and Electrolytic Cells  1.10.3. Nernst equation  1.10.4. Electrolysis  1.10.5. Faraday's laws of electrolysis  1.11. Thermodynamics  1.11.1. Laws of Thermodynamics  1.11.2. Enthalpy, entropy and Gibbs free energy  1.11.3. Spontaneity of reactions  1.11.4. Thermodynamic cycles (Hess's law, Carnot cycle)  1.12. Kinetics  1.12.1. Rate law and reaction order  1.12.2. Activation Energy and Catalyst  1.12.3. Collision theory  1.12.4. Reaction mechanism  1.12.5. Transition state theory
  2. Organic chemistry  2.1. Structure and relationships  2.1.1. Hybridisation in Carbon Compounds  2.1.2. Resonance and aromatization  2.1.3. Molecular orbitals  2.1.4. Inductive and mesomeric effects  2.2. Hydrocarbons  2.2.1. Hydrocarbons  2.2.2. Alkene  2.2.3. Alkynes  2.2.4. Aromatic compounds  2.2.5. Cycloalkanes and Conformation  2.3. Functional Group  2.3.1. Alcohols and phenols  2.3.2. Ethers and epoxides  2.3.3. Aldehyde and ketone  2.3.4. Carboxylic acids and derivatives  2.3.5. Amin  2.3.6. Esters and amides  2.3.7. Thiols and sulfides  2.4. Stereoscopic  2.4.1. Isomerism in Stereochemistry  2.4.2. Chirality and optical activity  2.4.3. Structural analysis  2.4.4. Diastereomers and Enantiomers  2.5.1. Substitution reactions  2.5.2. Elimination reactions  2.5.3. Addition reactions  2.5.4. Radical reactions  2.5.5. Rearrangement reactions  2.5.6. Pericyclic Reactions  2.6. Spectroscopy and structural analysis  2.6.1. Infrared Spectroscopy  2.6.2. Nuclear magnetic resonance spectroscopy  2.6.3. Mass Spectrometry  2.6.4. UV-visible spectroscopy  2.6.5. X-ray crystallography  2.7. Polymer chemistry  2.7.1. Addition and Condensation Polymers  2.7.2. Polymerization mechanism  2.7.3. Biodegradable Polymer  2.7.4. Conducting and smart polymers
  3. Inorganic chemistry  3.1. Coordination chemistry  3.1.1. Ligands and coordination compounds  3.1.2. Crystal field theory  3.1.3. Molecular Orbital Theory in Coordination Compounds  3.1.4. Jahn–Taylor distortion  3.2. Main Group Chemistry  3.2.1. Alkali and alkaline earth metals  3.2.2. Halogens and Noble Gases  3.2.3. Transition metals and their complexes  3.2.4. Lanthanides and Actinides  3.3. Solid state chemistry  3.3.1. Crystal lattices and unit cells  3.3.2. Defects in solids  3.3.3. Electrical and magnetic properties  3.3.4. Superconductivity  3.4. Bio-inorganic chemistry  3.4.1. Metal ions in biology  3.4.2. Enzymatic reactions with metals  3.4.3. Metal poisoning and detoxification  3.4.4. Metalloproteins and Metalloenzymes
  4. Physical chemistry  4.1. Quantum Chemistry  4.1.1. Wave–particle duality  4.1.2. Schrödinger Equation  4.1.3. Quantum Numbers and Orbitals  4.1.4. Atomic and molecular spectroscopy  4.2. Statistical mechanics  4.2.1. Maxwell–Boltzmann distribution  4.2.2. Partitioning functions  4.2.3. Bose–Einstein and Fermi–Dirac statistics  4.3. Chemical thermodynamics  4.3.1. Gibbs Free Energy  4.3.2. Phase transition  4.3.3. Thermodynamic efficiency  4.4. Surface chemistry  4.4.1. Absorption and Catalysis  4.4.2. Colloids and Emulsions
  5. Analytical Chemistry  5.1. Classical methods  5.1.1. Gravimetric Analysis  5.1.2. titrimeter  5.2. Instrumental methods  5.2.1. Chromatography  5.2.2. Spectroscopy  5.2.3. Electroanalytical methods  5.2.4. X-ray diffraction
  6. Industrial Chemistry  6.1. Petrochemistry  6.2. Chemical engineering principles  6.3. Green Chemistry  6.4. Pharmaceuticals and Drug Synthesis
  7. Biochemistry  7.1. Carbohydrates  7.2. Proteins and enzymes  7.3. Lipids and membranes  7.4. Nucleic acids  7.5. Metabolism and Bioenergetics  7.6. Enzyme kinetics and mechanism

Undergraduate → Inorganic chemistry → Solid state chemistry ↓


Electrical and magnetic properties


Understanding the electrical and magnetic properties of materials is very important in solid state chemistry, especially when dealing with inorganic compounds. These properties often determine the usefulness and functionality of materials in various applications such as semiconductors, magnets, and electrical conductors. In this document, we will explore the nature of these properties, their origins, and the implications for the field of inorganic chemistry.

Electrical properties of solids

The electrical properties of solids primarily reflect how well a material can conduct electricity. This depends on the availability of charge carriers—electrons and holes. The electrical properties of materials can be classified into three different categories: conductors, semiconductors, and insulators.

Conductor

Conductors are materials that allow the flow of electrical charge due to the presence of free electrons. Metals such as copper (Cu) and aluminum (Al) are well-known conductors. Conductivity in these materials is due to the overlapping of their conduction band and valence band, allowing the electrons to move freely.

conduction band valence band Overlap

The above example shows how the conduction and valence bands in conductors overlap each other, facilitating the movement of free electrons.

Insulator

In contrast, insulators have a significant band gap, which prevents electrons from moving from the valence band to the conduction band, making them poor conductors of electricity. Materials such as glass or rubber fall into this category.

conduction band valence band band gap

This diagram shows the wide band gap in insulators, which impedes electron flow.

Semiconductors

Semiconductors have smaller band gaps than insulators, allowing electrons to cross the gap with minimal energy input, such as heat or light. Silicon (Si) and germanium (Ge) are the classic semiconductor materials.

conduction band valence band band gap

As shown above, the small band gap in semiconductors allows for easier electron transitions with energy input.

Factors affecting conductivity

The electrical conductivity of materials depends on a variety of factors, including temperature, impurities, and structural defects.

Temperature

For metals, increasing temperature decreases electrical conductivity because lattice vibrations increase, which scatters electrons. In contrast, increasing temperature in semiconductors can increase conductivity because more electrons gain enough energy to move into the band gap.

Impurities

Adding impurities to a semiconductor (called doping) can significantly affect its conductivity. Consider the following example:

Silicon mixture with phosphorus:

        Si + P → n-type semiconductor

Here, the addition of an extra electron to phosphorus (P) results in the formation of an n-type (negative-type) semiconductor by contributing the extra electrons as charge carriers.

Structural defects

Structural defects, such as vacancies or gaps, can also affect conductivity by disrupting the ordered arrangement of atoms, leading to more scattering events or non-radiative recombination sites.

Magnetic properties of solids

Magnetic properties arise from the motion of electrons and their spin. Depending on their magnetic behavior, materials can be classified into several categories, including diamagnetic, paramagnetic, ferromagnetic, antiferromagnetic, and ferrimagnetic.

Diamagnetism

Diamagnetic materials are those that create an induced magnetic field in the direction opposite to the applied magnetic field. This weak repulsion from a magnetic field is a universal property that all materials experience to some degree, although in many materials it is so weak as to be unnoticeable. An example of a diamagnetic material is bismuth (Bi).

Paramagnetism

Paramagnetic materials have unpaired electrons, resulting in magnetic dipoles that are randomly oriented. When exposed to an external magnetic field, the dipoles align with the field, producing a weak attraction. Examples include aluminum (Al) and oxygen (O2).

Before the field After the field

The above figure shows how the magnetic dipoles in paramagnetic materials align with the external magnetic field.

Ferromagnetism

Ferromagnetic materials exhibit strong, permanent magnetism due to the parallel alignment of magnetic dipoles in a domain. Common ferromagnetic materials include iron (Fe) and nickel (Ni).

Antiferromagnetism

Antiferromagnetic materials have equal numbers of magnetic dipoles aligned in opposite directions, which effectively negate each other, resulting in no macroscopic magnetism. Examples include manganese oxide (MnO).

Antiferromagnetic alignment

This view shows the opposite alignment of spins in antiferromagnetic materials.

Ferrimagnetism

Ferrimagnetic materials have unequal opposite magnetic dipoles, resulting in a net magnetic moment. Ferrites are common ferrimagnetic materials.

Implications and applications

Understanding the electrical and magnetic properties of materials has a huge impact in technological and industrial applications. These properties help design better semiconductors for electronic devices, efficient magnetic storage media, and advanced materials for innovation in technology.

Technical equipment

Semiconductor devices, such as diodes, transistors and integrated circuits, rely heavily on materials with precise electrical properties. Silicon-based technologies dominate, although alternatives such as gallium arsenide (GaAs) are used in niche applications such as mobile phones and satellites.

Magnetic storage

Magnetic properties are essential in data storage technologies, where ferromagnetic materials form the basis of hard disk drives. The alignment and organization of the magnetic domains allows the storage of binary data.

Conclusion

The electrical and magnetic properties of solids form the basis of many modern technological advancements. Understanding these properties at the atomic and molecular levels enables chemists and scientists to manipulate and use materials for a variety of practical applications, radically changing our technological landscape.


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Electrical and magnetic properties

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