WCO Explanatory Notes reproduced for reference. © World Customs Organization. Verify against official WCO publication.
28.42 - Other salts of inorganic acids or peroxoacids (including aluminosiJicates whether or not chemically defined), other than azides. 2842.10 - Double 2842.90 - Other or complex silicates, including aluminosilicates whether or not chemically defined Subject to the exclusions mentioned in the introduction to this sub-chapter, this heading includes : (I) SALTS OF NON-METAL INORGANIC ACIDS OR PEROXOACIDS NOT SPECIFIED ELSEWHERE Examples of these salts include : (A) Fulminates, cyanates, isoc anates and thioc anates, metal salts of the non-isolated cyanic acid (HO-CEN) or ofisocyanic acid (&=c=o) or of fulminic acid ( H - C = - 0 - ) another isomer of cyanic acid, or of thiocyanic acid (HS-CEN). (1) Fulminates. Fulminates are compounds of more or less unknown composition, very unstable, exploding at a slight shock or under the action of heat (for example, a s ark). They constitute priming explosives and are used in the manufacture of &lminating caps or detonators. (2) Cyanates. Ammonium, sodium or potassium cyanates are used for manufacturing various organic compounds. There are also cyanates of alkaline-earths. (3) Thiocyanates. Thiocyanates (sulphocyanides) are the metal salts of the non-isolated thiocyanic acid (HS-CW). The most important are : (a) Ammonium thiocyanate (NH4SCN). Colourless crystals, deli uescent, very soluble in water, turning red under the action of air and light, an?decomposed l by heat. Used in electroplating; in photography; in dyeing or printing (m particular to prevent the deterioration of sized silk fabrics); for preparing refiigeratin mixtures, c anides or hexacyanoferrates (II), thiourea, guanidine, plastics, a esives, wee -killers, etc. & bl (b) Sodium thiocyanate (NaSCN). Same ap earance as ammonium thiocyanate or as a powder. Poisonous. Used in p!l otography; in dyeing and printing (mordant); in medicine; as a laboratory reagent; in electroplating; for preparing artificial mustard oil; in the rubber industry, etc. as sodium in organic synthesis the preparation of (d) Calcium thiocyanate (Ca(SCN)2.3H20).Colourless crystals, deliquescent and soluble in water. Used as a mordant in dyeing or printing, and as a solvent for cellulose; for mercerising cotton; in medicme Instead of potassium iodide (against arteriosclerosis); for preparing hexacyanoferrates (11) or other thiocyanates; in the manufacture of parchment. (e) Copper thiocyanates. Cuprous thiocyanate (CuSCN), whitish, greyish or yellowish powder or paste, insoluble in water. Used as a mordant in textlle printing, in the manufacture of marine paints and in organic synthesis. Cupric thiocyanate (Cu(SCN)z), black powder, insoluble in water, readily turnin into cuprous thiocyanate. Used in the manufacture of detonating caps and o matches. ! Mercury Wrninate and mercuric thiocyanate are excluded (heading 28.52). (B) Arsenites and arsenates. These are the metal salts of acids of arsenic; arsenites are the salts of arsenious acids, and arsenates are the salts of arsenic acids (heading 28.11). They are violently poisonous. Examples are : (I) Sodium arsenite (NaAs02). Prepared by the fusion of sodium carbonate with arsenious oxide. White or greyish slabs or powder, soluble in water. Used in viticulture (insecticide); for preserving hides; in me&cine; in the manufacture of soap and antiseptics, etc. (2) Calcium arsenite (CaHAsO$. White powder, insoluble in water. Used as an insecticide. (3) Copper arsenite (CuAs03). Obtained from sodium arsenite and Green powder, insoluble in water. Used as an insecticide, as a known as Scheele's green and for preparing certain green pigments Note to heading 32.06). (4) Zinc arsenite (Zn(AsO2)z). Similar appearance and uses to calcium arsenite. (5) Lead arsenite (Pb(AsO2)2). White powder, only sparingly soluble in water. Used in viticulture (insecticide). (6) Sodium arsenates (ortho-, meta- and pyroarsenates). The most important are disodium hydrogen orthoarsenate (Na2HAs04)(with 7 or 12 H20, according to the temperature of crystallisation) and trisodium orthoarsenate (anhydrous or with 12 H20). Prepared from memous oxide and sodium nitrate. Colourless crystals or greenish powder. Used in the preparation of medicaments (Pearson's solution), of antiseptics, insecticides, and of other arsenates; also used in textile printing. (7) Potassium arsenates. Mono- and dibasic potassium orthoarsenates, prepared by the same method as sodium arsenates. Colourless crystals, soluble in water. Used as antiseptics or insecticides; for tanning; for printing textiles, etc. (8) Calcium arsenates. Tricalcium diorthoarsenate (Ca3(A~04)2), often containing other calcium arsenates as impurities. Obtained by the interaction of calcium chloride and sodium arsenate. White powder, insoluble in water. Used in agriculture as an insecticide. Obtained from sodium (9) Co per arsenates. Cupric orthoarsenate (CIXJ(ASO~)S. odoarsenate and copper sulphate (or chloride). Green powder, insoluble in water. Used as a parasiticide m viticulture and for preparing anti-fouling paints. (10) Lead arsenates. Trilead diorthoarsenate (Pb3(As0&), and the acid orthoarsenate. Only sparing1 soluble in water. White powders, pastes or emulsions. Used in the preparation o znsecticides. ? (1 1) Other arsenates. These include arsenates of aluminium (insecticide) or of cobalt (pink powder, used in ceramics). The heading does not cover : (a) Natural nickel arsenates (e-g., annabergite, etc.) (heading 25.30). @) Arsenides (heading 28.53). (c) Acetoarsenites (Chapter 29). (C) The salts of selenium acids : selenides, selenites, selenates. These include : (1) Cadmium selenide. Used in the manufacture of anti-glare glass and of pigments. (2) Sodium selenite. Used for giving glass a red tint, or for masking its greenish hue. (3) Ammonium and sodium selenates. Used as insecticides; the sodium salt is also used in medicine. (4) Potassium selenate. Used in photography. Zorgite, a natural copper lead selenide, is excluded (heading 25.30). (D) The salts of tellurium acids : tellurides, tellurites, tellurates. These include : (1) Bismuth telluride. A semi-conductor for thermopiles. (2) Sodium or potassium tellurates. Used in medicine. (IT)DOUBLE OR COMPLEX SALTS This group covers double or complex salts other than those specifically included elsewhere. The principal double or complex salts classified in this heading include : (A) Double or complex chlorides (chlorosalts). (1) Chloride of ammonium with : (a) Magnesium. Deliquescent crystals; used in soldering. (b) Iron (ammonium ferrous chloride and ammonium ferric chloride). In masses or hygroscopic crystals; used in plating and in medicine. (c) Nickel. Yellow powder or, hydrated, green crystals. Used as a mordant and in galvanising. (d) Copper (ammonium copper chloride). Blue or greenish crystals, soluble in water, Used as a colouring agent and in pyrotechnics. (e) Zinc (ammonium zinc chloride). White crystalline powder, soluble in water. Used in soldering (" soldering salts "), in dry batteries, and in galvanising (electrolytic zinc-plating). (f) Tin. In particular ammonium chlorostannate; white or ink crystals or in aqueous solution. Sometimes called " pink salt "; used in yeing and as a size for silk. B (2) Chloride of sodium with aluminium. White crystalline powder, hygroscopic. Used in tanning. (3) Chloride of calcium with magnesium. White deliquescent crystals. Used in the paper, textile, potato-starch or pant industries. (4) Chlorosalts, e.g., chlorobromides, chloroiodides, chlorophosphates, chlorochromates and chlorovanadates. chloroiodates, These include potassium chlorochromate (Peligot's salt Red crystals, decomposing in water. It is an oxidising agent used in organic syntkesis. Pyrornorphite Cphos hate and chloride of lead) and vanadinite (vanadate and chloride of lead) are exeluded smce %ey are natural metallic ores of headings 26.07 and 26.15, respectively. (B) Double or complex iodides (iodosalts). (1) Bismuth sodium iodide. Red crystals, decomposed by water. Used in medicine. (2) Cadmium potassium iodide. A white deliquescent powder which turns yellow on exposure to air. Also used in medicine. (C) Double or complex salts containing sulphur (thiosalts). (1) Sulphate of ammonium with : (a) Iron (ammonium ferrous sulphate, Mohr's salt) (FeSO~.(NH4)2S0,.6H,O). Light green crystals, soluble in water. Used in metallurgy and in medicine. P' (b) Cobalt (CoS04. 13&S04.6H20). Red crystals, soluble in water. Used in cobalt-plating an in ceramics. (c) Nickel (NiSO4.(N&)2SO4.6H20). Green crystals, decomposed by heat; very soluble in water. Used mainly for electrol*~ nickel-plating. (d) Copper. Blue crystalline powder soluble in water, eMorescing in air. Used as a parasiticide, in textile prmting and processing, in the preparation of copper arsenite, etc. (2) Sodium zirconium sulphate. White solid. Used in zinc metallurgy. (3) bLThiosalts"and other double or complex salts containing sulphur, e.g. : selenosulphides and selenosulphates, thiotellurates, thioarsenates, thioarsenites and arsenosulphides, thiocarbonates, germanosulphides, thioantimonates, thiomolybdates, thiostannates, reineckates. This group includes : (a) Potassium trithiocarbonate. Yellow crystals, soluble in water. Used in agriculture (against phylloxera) and in chemical analysis. (b) Alkali thiomolybdates. Used as accelerating agents in metal phosphatising (pukerising) baths. (c) Ammonium tetrathiocyanatodiamminochromate (ammonium diamminetetrakisthioc anatochromate, ammonium reineckate or reinecke salt) m [ ~ r ( ~ ~ $ 2 ( ~ ~ ~Crystalline 4 ) I . ~ powder ~ ~ ) .or dark red crystals. Used as a reagent. (d) Ferrous potassium thiocyanate and ferric potassium thiocyanate. Cobaltite (sulphide and arsenide of cobalt) and gerrnanite (co per gerrnano-sulphide) are excluded fiom this heading since they are natural ores of eadings 26.05 and 26.17, respectively. i @) Double or complex salts of selenium (selenocarbonates, selenocyanates, etc.). (E) Double or complex salts of tellurium (tellurocarbonates, tellurocyanates, etc.). (F) Cobaltinitrites (nitrocobaltates). Potassium cobaltinitrite (cobalt otassium nitrite, Fischer's yellow) (K~CO(?JO~)~). Microcrystalline powder, fairly so uble in water. A pigment which, alone or mxed, is known as cobalt yellow. P (G) Double or complex nitrates (tetra- and hexa-amminonickel nitrates). Ammoniacal nickel nitrates. Blue or green water soluble crystals. Used as oxidants and for the preparation of the pure nickel catalyst. (H) Double or complex phosphates (phosphosalts). (1) Ammonium sodium orthophosphate NaNH4HP04.H2T (microcosmic salt). Colourless efflorescent crystals, soluble in water. Used as a ux for dissolving metal oxides. (2) Ammonium magnesium orthophos hate. White owder, only very slightly soluble in water. Used for fire-proofing texti es and in me cine. (3) Complex salts containing phosphorus, e.g., silicophosphates, tungstophosphates, stannophosphates. P molybdophosphates, This group includes : (a) Molybdophosphates. Used in microscopic research. (b) Silicophosphates and stannophosphates. Used for sizing silk. (IT) Tungstoborates (borotungstates). Cadmium borotungstate. Yellow crystals or in aqueous solution. Used for separating minerals by density. (K)DoubIe or complex cyanates. (L) Double or complex silicates. This grou includes aIuminosilicates,whether or not they are separate chemically defined compoun s. Alurninosilicates are used in the glass industry and as insulators, ionexchangers, catalysts, molecular sieves, etc. g are synthetic zeolites with the generic formula Included in this catego Mun0.A1203.ySiOz.wH20, w ere M is a cation of valenc n (usually sodium, potassium, magnesium or calcium), y is two or more and w is the nurn er of water molecules. Y g Aluminosilicates containin binders (e-g., zeolites containing, silica-bas+ clay) are, however, excluded (heading 38.24).h+ticle size can usualy be used to identify zeolites containing blnders (usually above 5 m~crons). (M) Double or complex salts of metal oxides. These are salts such as calcium potassium chromate. This heading excludes (a) Complex fluorine salts (heading 28.26). (b) Alums (heading 28.33). (c) Complex cyanides (heading 28.37). (d) Salts of hydrazoic acid (azides) (heading 28.50). (e) Chloride of ammonium with mercury ammonium mercuric chloride or ammonium chloromercurate) and copper mercury iodide (heading 2 .52). il (9 Magnesium potassium sulphate, whether or not pure (Chapter 31). Sub-chapter VI MISCELLANEOUS
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.