WCO Explanatory Notes reproduced for reference. © World Customs Organization. Verify against official WCO publication.
28.29 Chlorates and perchlorates; bromates and perbromates; iodates and periodates. 2829.1 1 2829.19 2829.90 - Chlorates : - - Of sodium - - Other - Other Subject to the exclusions s ecified in the introduction to this sub-chapter, this heading covers chlorates and perohlorates, gomates and prbromates, and iodates and periodates of metals. (A) CHLORATES This group covers the salts of chloric acid (HC10$ (heading 28.1 1). (1) Sodium chlorate (NaC103). Obtained by electrolysin an aqueous solution of sodium chloride. Shiny colourless crystals (tablets); v e y solu le in water; readily 'ves off its Often contains impurities (e.g., chlorides of the alkali metals). sed as an OX%=0x1 'sing agent, in organic synthesis, in textile printing aniline black dyes for the manufacture of hlminating primers and preparations for matc heads, as a weed-Aller, ctc. % b (2) Potassium chlorate (KC103). Prepared in a similar manner to sodium chlorate. Colourless crystals, s arin ly soluble in water. Its other properties are similar to those of sodium chlorate. t is a so used in medicine and in the manufacture of blasting explosives (e.g., cheddite). 7 7 (3) Barium chlorate (Ba(C103)2).Obtained by electrolysing a solution of barium chloride; colourless crystals, soluble in water. Used as green colounng matter in pyrotechnics and in the manufacture of explosives and certain other chlorates. (4) Other chlorates. These include ammonium chlorate, used in the manufacture of explosives; strontium chlorate, used in the manufacture of explosives and in pyrotechnics to produce red lights; chromium chlorate, used as a mordant in dyeing; copper chlorate, green crystals used in dyeing, in the manufacture of explosives and m pyrotechnics to produce green lights. (B) PERCHLORATES This group covers the salts of perchloric acid (HC104) (heading 28.11). These powerful oxidislng agents are used in pyrotechnics and in the manufacture of explosives. (1) Ammonium erchlorate (NH4C104). Prepared from sodium perchlorate. Colourless crystals, solub e in water especially when hot; decomposed by heat, sometimes explosively. P (2) Sodium erchlorate (NaC104). Obtained by electrolysing cold solutions of sodium f chlorate; eliquescent, colourless crystals. (3) Potassium perchlorate (KC104).Obtained fiorn sodium perchlorate. Colourless crystalline powder of comparatively low solubility, ex lodng on shock. Used in the chemical industry as an oxidising agent more powerful than c lorates. R (4) Other perchlorates. These include : barium perchlorate (h drated powder) and lead perchlorate; the saturated solution of the latter is a heavy liqui (specific gravity 2.6) used xn the flotation process. 2' (C) BROMATES AND PERBROMATES This group covers the salts of bromic acid (HBr03) heading 28.11), for example potassium bromate (KBrOl), and the salts of perbromic acid (Hl31-b~). (D) IODATES AND PERIODATES This g o u covers the salts of iodic acid (HIo3)(heading 28.1 1) and the salts of periodic acid (heading 8. I 1). I Sodium iodate (NaI03), potassium iodate (KI03 and potassium hydrogen di-iodate (KH(I03)2) are employed in medicine and as reagents in c emical analysis. Barium iodate, in crystals, is used for manufacturing iodic acid. b Sodium periodates (monosodium and disodium) are obtained by the action of chlorine on an alkaline solution of sodium iodate.
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.