Periodic System for Chemists
Table
5
10.81

B

Boron

Identification

CAS Number: 7440-42-8
Discovery Year: 1808
Discoverer: Sir H. Davy, J.L. Gay-Lussac, L.J. Thénard
Discovery Location: England/France

Properties

Atomic Mass: 10.81 →Density: 2.34 g/cm³ →
Crust Abundance: 10 mg/kg
Crystal Structure: TET

Atomic Dimensions

Atomic Radius: 85 pm →
Atomic Radius (Rahm): 204.99999999999997 pm
Covalent Radius: 84 pm →
Van der Waals Radius: 192 pm
Metallic Radius: 80 pm
Atomic Volume: 4.6 cm³/mol
Lattice Constant: 8.73 Å

Thermodynamics

Melting Point: 2573 K →Boiling Point: 3931 K →Specific Heat: 1.025 J/(g·K) →Thermal Conductivity: 27.4 W/(m·K) →Heat of Fusion: 23.6 kJ/mol →Heat of Vaporization: 504.5 kJ/mol →
Heat of Formation: 565 kJ/mol

Electronic Structure

Electron Config: [He] 2s2 2p
Block: p
Period: 2 →Group: 13 →Electronegativity: 2.04 →Electron Affinity: 0.279723 eV →
Oxidation States: +3

Abundance & Geochemistry

Crust Abundance: 10 mg/kg
Sea Abundance: 4.44 mg/L
Goldschmidt Class: litophile

About

Boron is a metalloid that is essential for plant growth and is used in fiberglass, detergents, and as a neutron absorber in nuclear reactors.

Isotopes

B-11 11 79.60%
B-10 10 20.40%