2811 19 80 60: Phosphorous acid, in solid or liquid (aqueous) forms, also denominated phosphonic acid, usually falling under chemical abstracts service ('cas') numbers 13598-36-2 and 10294-56-1. the customs and statistics (‘cus’) numbers usually corresponding to this product are 0021895-1 and 0043878-8.

1. Except where the context otherwise requires, the headings of this chapter apply only to:

1. (a) separate chemical elements and separate chemically defined compounds, whether or not containing impurities;

2. (b) the products mentioned in (a) above dissolved in water;

3. (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;

4. (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;

5. (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), carbonates and peroxocarbonates of inorganic bases (heading 2836), cyanides, cyanide oxides and complex cyanides of inorganic bases (heading 2837), fulminates, cyanates and thiocyanates, of inorganic bases (heading 2842), organic products included in headings 2843 to 2846 and 2852 and carbides (heading 2849), only the following compounds of carbon are to be classified in this chapter:

1. (a) oxides of carbon, hydrogen cyanide and fulminic, isocyanic, thiocyanic and other simple or complex cyanogen acids (heading 2811);

2. (b) halide oxides of carbon (heading 2812);

3. (c) carbon disulphide (heading 2813);

4. (d) thiocarbonates, selenocarbonates, tellurocarbonates, selenocyanates, tellurocyanates, tetrathiocyanatodiamminochromates (reineckates) and other complex cyanates, of inorganic bases (heading 2842);

5. (e) hydrogen peroxide, solidified with urea (heading 2847), carbon oxysulphide, thiocarbonyl halides, cyanogen, cyanogen halides and cyanamide and its metal derivatives (heading 2853) other than calcium cyanamide, whether or not pure (Chapter 31).

3. Subject to the provisions of note 1 to Section VI, this chapter does not cover:

1. (a) sodium chloride or magnesium oxide, whether or not pure, or other products of Section V;

2. (b) organo-inorganic compounds other than those mentioned in note 2 above;

3. (c) products mentioned in note 2, 3, 4 or 5 to Chapter 31;

4. (d) inorganic products of a kind used as luminophores, of heading 3206; glass frit and other glass in the form of powder, granules or flakes, of heading 3207;

5. (e) artificial graphite (heading 3801); products put up as charges for fire-extinguishers or put up in fire-extinguishing grenades, of heading 3813; ink removers put up in packings for retail sale, of heading 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;

6. (f) precious or semi-precious stones (natural, synthetic or reconstructed) or dust or powder of such stones (headings 7102 to 7105), or precious metals or precious-metal alloys of Chapter 71;

7. (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

8. (h) optical elements, for example, of the halides of the alkali or alkaline-earth metals (heading 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.

5. Headings 2826 to 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.

6. Heading 2844 applies only to:

1. (a) technetium (atomic No 43), promethium (atomic No 61), polonium (atomic No 84) and all elements with an atomic number greater than 84;

2. (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;

3. (c) compounds, inorganic or organic, of these elements or isotopes, whether or not chemically defined, whether or not mixed together;

4. (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);

5. (e) spent (irradiated) fuel elements (cartridges) of nuclear reactors;

6. (f) radioactive residues whether or not usable.

The term ‘isotopes’, for the purposes of this note and of the wording of headings 2844 and 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 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.