Yttrium Borides - YB₂ (yttrium Diboride)

YB₂ (yttrium Diboride)

Yttrium diboride has the same hexagonal crystal structure as aluminium diboride and magnesium diboride – an important superconducting material. Its Pearson symbol is hP3, space group P6/mmm (No 191), a = 0.3289 nm, b = 0.3289 nm, c = 0.3843 nm and the calculated density is 5.1 g/cm3. In this structure, the boron atoms form graphite like sheets with yttrium atoms between them. YB₂ crystals are unstable to moderate heating in air – they start oxidizing at 400 °C and completely oxidize at 800 °C. YB₂ melts at ~2220 °C.