Boron ( B )

• Atomic number: 5
• Appearance: white-gray metallic
• Standard atomic weight: 10.81
• Group: group 13 (boron group)
• Period: 2
• Electron configuration: 1s² 2s² 2p¹
• Element category: metalloid
• Melting point: 2349 K
• Boiling point: 4200 K
• Sublimation point:
Standard Temperature ( 273.15 ) and Pressure ( 1 bar = 10⁵ Pa )
• Phase at STP: solid
• Density at STP:
• Heat of fusion: 50.2 kJ/mol
• Heat of vaporization: 508 kJ/mol
• Molar heat capacity: 11.087 kJ/(mol·K)
• Oxidation states: 0 +1 +2
• Electronegativity: Pauling scale: 1.57
• Covalent radius: 96 pm (1×10⁻¹² m)
• Van der Waals radius: 153 pm (1×10⁻¹² m)
• Crystal structure:
• Speed of sound: 12890 m/s (at 20 °C)
• Thermal expansion: 11.3 µm/(m·K)
• Thermal conductivity: 200 W/(m·K)