Section 06 Products of the chemical or allied Industries 28 Inorganic chemicals; organic or inorganic compounds of precious metals, of rare-earth metals, of radioactive elements or of isotopes 28 50 Hydrides, nitrides, azides, silicides and borides, whether or not chemically defined, other than compounds which are also carbides of heading 28.49 Commodity Code Description 28 50 00 Hydrides, nitrides, azides, silicides and borides, whether or not chemically defined,