PHD
  1. Inorganic chemistry  1.1. Coordination chemistry  1.1.1. Ligand field theory  1.1.2. Crystal field theory  1.1.3. Molecular Orbital Theory for Coordination Compounds  1.1.4. Stability of Coordination Compounds  1.1.5. Electronic spectra of coordination compounds  1.1.6. Isomerism in Coordination Compounds  1.1.7. Kinetics and mechanism of coordination reactions  1.2. Organometallic Chemistry  1.2.1. Metal Carbonyls  1.2.2. Metal alkyl and aryl  1.2.3. Fischer and Schrock carbonaceans  1.2.4. Oxidative Addition and Reductive Elimination  1.2.5. Metal Hydrides  1.2.6. Catalysis by organometallic compounds  1.2.7. Metallocenes and Sandwich Complexes  1.2.8. CH activation  1.3. Solid state chemistry  1.3.1. Crystal structures and lattices  1.3.2. Band theory and electrical properties  1.3.3. Defects in the crystal  1.3.4. Synthesis of solid state materials  1.3.5. Magnetic and optical properties of solids  1.3.6. Superconductivity  1.3.7. Solid state ionics  1.4. Bio-inorganic chemistry  1.4.1. Metalloproteins and enzymes  1.4.2. Metal ion transport and storage  1.4.3. The role of metals in medicine  1.4.4. Bioinspired catalysis  1.4.5. Metal–DNA interactions  1.4.6. Metal Complexes in Medical Science  1.5. Lanthanides and Actinides  1.5.1. Electronic configuration and oxidation states in lanthanides and actinides  1.5.2. Spectral and Magnetic Properties in Lanthanides and Actinides  1.5.3. Separation and Extraction of Lanthanides and Actinides  1.5.4. Coordination chemistry of f-block elements  1.6. Main Group Chemistry  1.6.1. Chemistry of boron compounds  1.6.2. Chemistry of Silicon and Germanium Compounds  1.6.3. Chemistry of Phosphorus and Sulfur Compounds  1.6.4. Organosilicon chemistry  1.6.5. Noble Gas Chemistry
  2. Organic chemistry  2.1. Reaction mechanism  2.1.1. Nucleophilic substitution reactions  2.1.2. Electrophilic addition and substitution reactions  2.1.3. Elimination reactions  2.1.4. Rearrangement reactions  2.1.5. Radical reactions  2.1.6. Pericyclic Reactions  2.1.7. Photochemical reactions  2.2. Stereoscopic  2.2.1. Chirality and optical activity  2.2.2. Structural analysis  2.2.3. Stereoelectronic effects  2.2.4. Asymmetric synthesis  2.2.5. Dynamic Stereochemistry  2.3. Organometallic Chemistry in Organic Synthesis  2.3.1. Organolithium and organomagnesium reagents  2.3.2. Transition metal catalyzed coupling reactions  2.3.3. Palladium-catalyzed reactions  2.3.4. Olefin Metathesis  2.3.5. Gold and silver catalysis  2.4. Natural products chemistry  2.4.1. Alkaloids and terpenoids  2.4.2. Steroids and Flavonoids  2.4.3. Total synthesis of natural products  2.4.4. Biosynthesis of natural products  2.5. Supramolecular Chemistry  2.5.1. Host-Guest Chemistry  2.5.2. Self-assembly and molecular recognition  2.5.3. Supramolecular Catalysis  2.5.4. Molecular Machines
  3. Physical Chemistry  3.1. Thermodynamics  3.1.1. Laws of Thermodynamics  3.1.2. Chemical Potential and Equilibrium  3.1.3. Statistical thermodynamics  3.1.4. Non-equilibrium thermodynamics  3.2. Quantum Chemistry  3.2.1. Schrödinger equation and its applications  3.2.2. Molecular orbital theory  3.2.3. Density functional theory  3.2.4. Post-Hartree–Fock methods  3.3. Chemical kinetics  3.3.1. Reaction rate theory  3.3.2. Mechanism and rate laws  3.3.3. Catalysis and enzyme kinetics  3.3.4. Reaction dynamics  3.4. Spectroscopy and molecular structure  3.4.1. Infrared Spectroscopy  3.4.2. UV-visible spectroscopy  3.4.3. Nuclear Magnetic Resonance Spectroscopy  3.4.4. Mass Spectrometry  3.4.5. Raman Spectroscopy  3.5. Surface and Colloid Chemistry  3.5.1. Absorption and Catalysis  3.5.2. Surfactants and micelles  3.5.3. Colloidal Stability  3.5.4. Nanomaterials and Interfaces
  4. Analytical chemistry  4.1. Chromatography  4.1.1. Gas Chromatography  4.1.2. High Performance Liquid Chromatography  4.1.3. Thin Layer Chromatography  4.1.4. Ion Chromatography  4.2. Electroanalytical techniques  4.2.1. Voltammetry and Polarography  4.2.2. Conductometry and potentiometry  4.2.3. Colometry  4.3. Spectroscopic Methods  4.3.1. Atomic absorption spectroscopy  4.3.2. Fluorescence Spectroscopy  4.3.3. X-ray diffraction  4.3.4. Electron paramagnetic resonance spectroscopy  4.4. Chemometrics  4.4.1. Data processing and statistical methods  4.4.2. Multidisciplinary analysis  4.4.3. Machine Learning in Analytical Chemistry
  5. Theoretical and Computational Chemistry  5.1. Molecular dynamics simulation  5.2. Quantum chemistry methods  5.3. Computational drug design  5.4. Machine Learning in Chemistry  5.5. Ab initio molecular dynamics
  6. Biophysics and Medicinal Chemistry  6.1. Drug discovery and design  6.2. Enzyme kinetics and inhibition  6.3. Chemical biology approach  6.4. Protein-ligand interactions  6.5. Bioorthogonal chemistry
  7. Materials chemistry  7.1. Polymer chemistry  7.1.1. Polymerization mechanism  7.1.2. Functional Polymers  7.1.3. Biodegradable Polymer  7.1.4. Conducting and semiconducting polymers  7.2. Nano Chemistry  7.2.1. Nanoparticles and nanostructures  7.2.2. Carbon-based nanomaterials  7.2.3. Quantum dots  7.3. Energy and Environmental Chemistry  7.3.1. Battery and Fuel Cell Chemistry  7.3.2. Green chemistry and sustainable materials  7.3.3. Photocatalysis

PHD → Inorganic chemistry → Main Group Chemistry ↓


Chemistry of boron compounds


Boron is a fascinating element found in the periodic table, forming part of the p-block and belonging to group 13. Despite being a less abundant element, the unique chemical and physical properties of boron have important applications in a variety of fields, including organic synthesis, medicine and materials science. This document attempts to explore the chemistry of boron compounds within the scope of main group chemistry, focusing on their structures, bonding, reactivity and applications.

Overview of boron

Boron is a metalloid with the symbol B and atomic number 5. Unlike metals and nonmetals, boron exhibits characteristics of both categories. Its high ionization energy and absence of metallic bonding characteristics give boron unique abilities when forming compounds. Boron's small size and charge density make it highly effective at interacting with other elements, particularly through covalent bonding.

Occurrence and isolation

Boron is not found freely in nature; instead, it exists as a compound in minerals such as borax (Na 2 B 4 O 5 (OH) 4 ·8H 2 O) and kernite (Na 2 B 4 O 6 ·4H 2 O). Extraction of boron from these minerals usually involves chemical reduction processes.

Boron atom

Types of boron compounds

Boron forms a wide range of compounds, primarily through covalent bonding. These can be classified into several main types:

Boron hydrides

Boron hydrides, or boranes, are compounds composed of boron and hydrogen. The simplest borane is diborane (B 2 H 6), characterized by its electron-deficient and unique three-center two-electron bond. These compounds are quite reactive.

    B 2 H 6 + 3O 2 → B 2 O 3 + 3H 2 O

Organoboron compounds

These compounds contain carbon-boron bonds and are important in organic chemistry, particularly in synthesis. A well-known organoboron compound is boronic acid, which is used in Suzuki coupling reactions, important in the formation of carbon-carbon bonds.

    Rb(OH) 2 + R'-X + Pd(0) → RR' + HOB(OH) 2

Boron halides

Boron forms halides, with boron trifluoride (BF 3) being the most common. Boron halides often act as Lewis acids because they can accept electron pairs due to boron's electron deficiency.

    BF3 + NH3 → F3B - NH3

Structure and bonding in boron compounds

Boron's unique bonding arises from its electron configuration 2s 2 2p 1. This allows boron to form trigonal planar bonds, but in some cases, as seen in borane, it forms multi-center bonds that are important in stabilizing electron-deficient structures.

3-Center 2-Electron Bonds: A prime example of boron's unique bonding ability is the stabilization of diborane (B 2 H 6) via 3-center 2-electron bonds. These bonds involve the sharing of two electrons between the three atoms, effectively reducing the electron deficiency.

BHB

Reactivity of boron compounds

Boron compounds are versatile in their reactions. Their reactivity is often determined by the electron deficiency of boron, causing it to act as a Lewis acid, seeking electron pairs to achieve a stable octet.

Reaction with oxygen

Boron readily forms oxides when heated in the presence of oxygen. Common among these compounds is boron trioxide (B 2 O 3), a glass-forming oxide that plays an important role in the manufacture of borosilicate glass.

Reaction with water

Some boranes react vigorously with water, while others, such as boron trifluoride, hydrolyse slowly.

    2B 2 H 6 + 6H 2 O → 4B(OH) 3 + 6H 2

Reactions with halogens

When reacting with halogens, boron forms trihalides such as boron trifluoride and boron trichloride, which are strong Lewis acids.

Applications of boron compounds

Boron compounds have wide applications due to their unique properties:

In materials science

Boron carbide and boron nitride are used in the production of high-strength, lightweight materials that are extremely important for mining equipment and military armor.

In medicine

Boron's biological roles have made it important in medical research. Boron-neutron capture therapy (BNCT) is a promising treatment for certain types of cancer.

In the catalyst

Boron's role as a catalyst is well known, especially its use in the Suzuki–Miyaura coupling, which is a valuable reaction in the synthesis of biaryl compounds in pharmaceuticals.

Conclusion

The chemistry of boron compounds is vast and highly complex. From its unique bonding systems to its versatile reactivity and diverse applications, boron chemistry stands as a vibrant field of study within inorganic chemistry. Understanding boron compounds provides insight into their profound impact on technology and innovation.


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Chemistry of boron compounds

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