Section 06 Products of the chemical or allied 28 Inorganic chemicals; organic or inorganic compounds of precious metals, of rare earth metals, of radioactive elements or isotopes 28 11 Other inorganic acids and other inorganic oxygen compounds of non-metals Commodity Code Description 28 11 11 - - Hydrogen fluoride (hydrofluoric acid) 28 11 12 - - Hydrogen cyanide (hydrocyanic acid) 28 11 19 - - Other 28 11 21 - - Carbon dioxide 28 11 22 - - Silicon dioxide 28 11 29 - - - Nitrous oxide