BiH3 hafnium silicides phosphides AlN Rb2O metal TiBr4 allotropy molybdate triflates metalorganics tetrahalides DyLight astatine skeuomorphic VCl4 intermetallic O2Qampminus WO3 metalloids divalent nitride borides chalcogenides NbO2 alkali Deprotonation Deathchain chalcogens Ruthenium metalloid osmium halide oxides