Oxide and peroxides of sodium are stable (Na2O and Na2O2) K,Rb,Cs form superoxides. Beryllium forms a hydride with molecular formula BeH2Organic lead (tetraethyl lead; TEL) is used as an antiknock agent in gasoline and jet fuels. The compound (NH4)2BeF4 on thermal decomposition produces BeF2 and NH4F.