201112 Carbon dioxide and other inorganic oxygen compounds of non-metals

20111230 Carbon dioxide 20111250 Sulphur trioxide (sulphuric anhydride)/ diarsenic trioxide 20111270 Nitrogen oxides 20111290 Inorganic oxygen compounds of non metals (excluding sulphur trioxide (sulphuric anhydride)/ diarsenic trioxide, nitrogen oxides, silicon dioxide, sulphur dioxide, carbon dioxide)