Boron - The Periodic Table part 8
Elemental symbol: B Atomic number: 5 Group: Metalloid Stable Isotopes: 11 B (common boron), 10 B Some Radioactive Isotopes: 6 B, 7 B, 8 B, 9 B, 12 B, 13 B, 14 B, 15 B, 16 B, 17 B, 18 B, 19 B, 20 B, 21 B Some Allotropes: Alpha tetragonal boron, alpha rhombohedral boron, beta rhombohedral boron Melting point: 2350K, 2077°C, or 3771°F Boiling point: 4273K, 4000°C, or 7232°F State at room temperature (20°C/68°F): Solid Density: 2.37 g/cm 3 Common compounds: sodium borate/borax (Na 2 [B 4 O 5 (OH) 4 ]⋅8H 2 0), boric acid (H 3 BO 3 ), boron nitride (BN), boron carbide (B 4 C) and many more... Discovered by: Louis-Josef Gay-Lussac and Louis-Jacques Thénard independently from Humphry Davy in 1808 Boron in a hard but brittle gray metal. For the reason that it’s brittle, boron is used mostly in compounds. Boron nitride (BN) makes crystals similar to crystals that carbon (C) can create. Cubic boron nitride is very hard, and under certain definitions of ‘hard’, i...