… Hydrides, nitrides, azides, silicides and borides, whether or not chemically defined, other than compounds which are also carbides of heading 28.49. …
Explanatory notes
… 28.50 ‑ Hydrides, nitrides, azides, silicides and borides, whether or not chemically defined, other than compounds which are also carbides of heading 28.49. The four groups of compounds … heading each contain two or more elements, one of which is described by the term used (hydrogen, nitrogen, silicon or …