Chapter 28 — Inorganic chemicals; organic or inorganic compounds of precious metals, of rare-earth metals, of radioactive elements or of isotopes

1. Except where the context otherwise requires, the headings of this chapter apply only to: (a) separate chemical elements and separate chemically defined compounds, whether or not containing impurities; (b) the products mentioned in (a) above dissolved in water; (c) the products mentioned in (a) above dissolved in other solvents provided that the solution constitutes a normal and necessary method of putting up these products adopted solely for reasons of safety or for transport and that the solvent does not render the product particularly suitable for specific use rather than for general use; (d) the products mentioned in (a), (b) or (c) above with an added stabiliser (including an anti-caking agent) necessary for their preservation or transport; (e) the products mentioned in (a), (b), (c) or (d) above with an added anti-dusting agent or a colouring substance added to facilitate their identification or for safety reasons, provided that the additions do not render the product particularly suitable for specific use rather than for general use. 2. In addition to dithionites and sulphoxylates, stabilised with organic substances (heading [2831](/headings/2831)), carbonates and peroxocarbonates of inorganic bases (heading [2836](/headings/2836)), cyanides, cyanide oxides and complex cyanides of inorganic bases (heading [2837](/headings/2837)), fulminates, cyanates and thiocyanates, of inorganic bases (heading [2842](/headings/2842)), organic products included in heading [2843](/headings/2843) to [2846](/headings/2846) and [2852](/headings/2852) and carbides (heading [2849](/headings/2849)), only the following compounds of carbon are to be classified in this chapter: a. oxides of carbon, hydrogen cyanide and fulminic, isocyanic, thiocyanic and other simple or complex cyanogen acids (heading [2811](/headings/2811)); b. halide oxides of carbon (heading [2812](/headings/2812)); c. carbon disulphide (heading [2813](/headings/2813)); d. thiocarbonates, selenocarbonates, tellurocarbonates, selenocyanates, tellurocyanates, tetrathiocyanatodiamminochromates (reineckates) and other complex cyanates, of inorganic bases (heading [2842](/headings/2842)); e. hydrogen peroxide, solidified with urea (heading [2847](/headings/2847)), carbon oxysulphide, thiocarbonyl halides, cyanogen, cyanogen halides and cyanamide and its metal derivatives (heading [2853](/headings/2853)) other than calcium cyanamide, whether or not pure (Chapter [31](/chapters/31)). 3. Subject to the provisions of note 1 to Section VI, this chapter does not cover: (a) sodium chloride or magnesium oxide, whether or not pure, or other products of Section V; (b) organo-inorganic compounds other than those mentioned in note 2 above; (c) products mentioned in note 2, 3, 4 or 5 to Chapter [31](/chapters/31); (d) inorganic products of a kind used as luminophores, of heading [3206](/headings/3206); glass frit and other glass in the form of powder, granules or flakes, of heading [3207](/headings/3207); (e) artificial graphite (heading [3801](/headings/3801)); products put up as charges for fire-extinguishers or put up in fire extinguishing grenades, of heading [3813](/headings/3813); ink removers put up in packings for retail sale, of heading [3824](/headings/3824); cultured crystals (other than optical elements) weighing not less than 2.5 g each, of the halides of the alkali or alkaline-earth metals, of heading [3824](/headings/3824); (f) precious or semi-precious stones (natural, synthetic or reconstructed) or dust or powder of such stones (heading [7102](/headings/7102) to [7105](/headings/7105)), or precious metals or precious-metal alloys of Chapter [71](/chapters/71); (g) the metals, whether or not pure, metal alloys or cermets, including sintered metal carbides (metal carbides sintered with a metal), of Section XV; or (h) optical elements, for example, of the halides of the alkali or alkaline-earth metals (heading [9001](/headings/9001)). 4. Chemically defined complex acids consisting of a non-metal acid of sub-chapter II and a metal acid of sub-chapter IV are to be classified in heading [2811](/headings/2811). 5. Headings [2826](/headings/2826) to [2842](/headings/2842) apply only to metal or ammonium salts or peroxysalts. Except where the context otherwise requires, double or complex salts are to be classified in heading [2842](/headings/2842). 6. Heading [2844](/headings/2844) applies only to: (a) technetium (atomic No 43), promethium (atomic No 61), polonium (atomic No 84) and all elements with an atomic number greater than 84; (b) natural or artificial radioactive isotopes (including those of the precious metals or of the base metals of Sections XIV and XV), whether or not mixed together; (c) compounds, inorganic or organic, of these elements or isotopes, whether or not chemically defined, whether or not mixed together; (d) alloys, dispersions (including cermets), ceramic products and mixtures containing these elements or isotopes or inorganic or organic compounds thereof and having a specific radioactivity exceeding 74 Bq/g (0.002 μCi/g); (e) spent (irradiated) fuel elements (cartridges) of nuclear reactors; (f) radioactive residues whether or not usable. The term ‘isotopes’, for the purposes of this note and of the wording of heading [2844](/headings/2844) and [2845](/headings/2845), refers to: - individual nuclides, excluding, however, those existing in nature in the monoisotopic state, - mixtures of isotopes of one and the same element, enriched in one or several of the said isotopes, that is, elements of which the natural isotopic composition has been artificially modified. 7. Heading [2853](/headings/2853) includes copper phosphide (phosphor copper) containing more than 15 % by weight of phosphorus. 8. Chemical elements (for example, silicon and selenium) doped for use in electronics are to be classified in this chapter, provided that they are in forms unworked as drawn, or in the form of cylinders or rods. When cut in the form of discs, wafers or similar forms, they fall in heading [3818](/headings/3818). ### Subheading note 1. For the purposes of subheading [2852 10](/commodities/2852100000), the expression ‘chemically defined’ means all organic or inorganic compounds of mercury meeting the requirements of paragraphs (a) to (e) of note 1 to Chapter [28](/chapters/28) or paragraphs (a) to (h) of note 1 to Chapter [29](/chapters/29). ### Additional chapter note 1. Unless provided otherwise, the salts specified in subheadings include acid salts and basic salts.