WCO Explanatory Notes reproduced for reference. © World Customs Organization. Verify against official WCO publication.
29.31 Other organo-inorganic compounds. 2931.10 - Tetramethyl lead and tetraethyl lead 293 1.20 - Tributyltin compounds 2931.90 - Other This heading includes : \ (1) Tetramethyl lead (Pb(CH3)4)and tetraethyl lead (Pb C2H5)4). Volatile liquids, colourless in the pure state, whereas the technical products are ye1 ow; toxic; very efficient anti-knock agents. (2) Tributyltin compounds. (3) Organo-silicon compounds. These are separate chemically defined compounds in which the silicon atom is dlrectly linked to at least one carbon atom of an organic radical. These compounds include organic silanes and siloxanes; in some cases these products are polymerized to make silicones. Silanes include chlorosilanes (e.g., dimethyldichlorosilane),alkoxysilanes (e.g., methyltrimethox silane), alkyl or aryl silanes (e.g., diphenylsilanediol, tetramethylsilane) and other mu tifunctional (amino, nitrile, ox~ranvl. oximo. acetoxv. etc.) silanes. Siloxanes include hexamethvldisiloxane. ~ctarn~th~ltrisiloxane, ockmethyfc clotetrasiloxane, decameth lcyclopenta~loxane and dodecamethylcyclohexasiloxanc. T e heading also includes examethyldisilazane and r K X This heading does not include inorganic silicon compounds, which are enaally classifiable in Chapter 28 (e.g., silicon tetrachlo.de (SiC4) in beadin 28.12 or trichl~msilanc( S ~ C Iin~ heading ) 28.53). Silicic acid esters and their salts are c l a u ~ f e dln he$. 29.20. Dellberate rnuhlres of re ?ate cbmucally defined ogano-silicon corn ounds are classified elsev%ere in the Nomenclature, general8 lo heading 38.24. This heading further excyudes noo-chemically defined products containin in the molecule mare than one siliconoxygen-silicon linkage, and containing organic groups connected to &e silicon atoms by direct s~licon-carbon bonds. These are sillcones of heading 39.10." (4) Iron carbonyl, nickel carbonyl, etc. (5) Organo-arsenic compounds. (a) Meth larsonic acid (CH3AsO(OH and its salts. Crystallises in flakes, and forms crysta line salts such as sodium metI! ylarsonate (colourless, used in medicine). i (b) Cacodylic acid and its salts. These contain the radical (-As(CH3)J known as cacodyl. Used in medicine. Cacodylic acid occurs as odourless, colourless crystals. Its main salt is sodium cacodylate, a crystalline white powder. (c) p-Aminophenylarsonic acid (HW6&AsO(OH)2) and its salts. Crystallises in shiny white needles. Its main salt is sodium p-aminophenylarsonate, an odourless, white, crystalline powder; used in medicine, particularly against sleeping-sickness. (d) Amino-hydroxyphenylarsonic acids, their formyl and acetyl derivatives and their salts. (e) Arsenobenzene (C6H5As=AsCa5)and its derivatives, compounds analogous to azo compounds but containing the arseno group (-As=A*) instead of the azo group (-N=N-). (6) 0-Iodosobenzoic acid. (7) Metal alkyls, metal fullerenes and metallocenes. (8) Organo-phosphorus compounds. These are organic compounds containing at least one phosphorus atom directly linked to a carbon atom. This group includes : (a) Dimethyl methylphosphonate. (b) Sodium 3-(trihydroxysily1)propyl methylphosphonate. (c) 0-Isopropyl methylphosphonofluoridate (sarin). (d) 0-Pinacolyl methylphosphonofluoridate(soman). This heading excludes organo-sulphur compounds whose molecules have sulphur atom(s) directly linked to carbon atom($ (see Note 6 to this Chapter). It excludes compounds whose molecules contail?, in addition to sulphur atom(s direct1 linked to carbon atom(s), other non-metal or metal atom($ dwectly l~nkedto carbon atotn(s) (e.g., dnoofos$SO)) (heading 29.30). This heading also excludes organo-mercury compounds which may contain one or more mercury atoms, in particular the (-HgX)group m which X is an inorganic or organic acid residue (heading 28.52). -
Notes. 1.- Except where the context otherwise requires, the headings of this Chapter apply only to : (a) Separate chemically defined organic compounds, whether or not containing impurities; (b) Mixtures of two or more isomers of the same organic compound (whether or not containing impurities), except mixtures of acyclic hydrocarbon isomers (other than stereoisomers), whether or not saturated (Chapter 27); (c) The products of headings 29.36 to 29.39 or the sugar ethers, sugar acetals and sugar esters, and their salts, of heading 29.40, or the products of heading 29.41, whether or not chemically defined; (d) The products mentioned in (a), (b) or (c) above dissolved in water; (e) The products mentioned in (a), (b) or (c) 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; (f) The products mentioned in (a), (b), (c), (d) or (e) above with an added stabiliser (including an anti- caking agent) necessary for their preservation or transport; (g) The products mentioned in (a), (b), (c), (d), (e) or (f) above with an added anti-dusting agent or a colouring or odoriferous substance or an emetic 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; (h) The following products, diluted to standard strengths, for the production of azo dyes : diazonium salts, couplers used for these salts and diazotisable amines and their salts. 2.- This Chapter does not cover : (a) Goods of heading 15.04 or crude glycerol of heading 15.20; (b) Ethyl alcohol (heading 22.07 or 22.08); (c) Methane or propane (heading 27.11); (d) The compounds of carbon mentioned in Note 2 to Chapter 28; (e) Immunological products of heading 30.02; (f) Urea (heading 31.02 or 31.05); (g) Colouring matter of vegetable or animal origin (heading 32.03), synthetic organic colouring matter, synthetic organic products of a kind used as fluorescent brightening agents or as luminophores (heading 32.04) or dyes or other colouring matter put up in forms or packings for retail sale (heading 32.12); (h) Enzymes (heading 35.07); (ij) Metaldehyde, hexamethylenetetramine or similar substances, put up in forms (for example, tablets, sticks or similar forms) for use as fuels, or liquid or liquefied-gas fuels in containers of a kind used for filling or refilling cigarette or similar lighters and of a capacity not exceeding 300 cm3 (heading 36.06); (k) Products put up as charges for fire-extinguishers or put up in fire-extinguishing grenades, of heading 38.13; ink removers put up in packings for retail sale, of heading 38.24; or (l) Optical elements, for example, of ethylenediamine tartrate (heading 90.01). 3.- Goods which could be included in two or more of the headings of this Chapter are to be classified in that one of those headings which occurs last in numerical order. 4.- In headings 29.04 to 29.06, 29.08 to 29.11 and 29.13 to 29.20, any reference to halogenated, sulphonated, nitrated or nitrosated derivatives includes a reference to compound derivatives, such as sulphohalogenated, nitrohalogenated, nitrosulphonated or nitrosulphohalogenated derivatives. Nitro or nitroso groups are not to be taken as “nitrogen-functions” for the purposes of heading 29.29. For the purposes of headings 29.11, 29.12, 29.14, 29.18 and 29.22, “oxygen function”, the characteristic organic oxygen-containing group of those respective headings, is restricted to the oxygen-functions referred to in headings 29.05 to 29.20. 5.- (A) The esters of acid-function organic compounds of sub-Chapters I to VII with organic compounds of these sub-Chapters are to be classified with that compound which is classified in the heading which occurs last in numerical order in these sub-Chapters. (B) Esters of ethyl alcohol with acid-function organic compounds of sub-Chapters I to VII are to be classified in the same heading as the corresponding acid-function compounds. (C) Subject to Note 1 to Section VI and Note 2 to Chapter 28 : (1) Inorganic salts of organic compounds such as acid-, phenol- or enol-function compounds or organic bases, of sub-Chapters I to X or heading 29.42, are to be classified in the heading appropriate to the organic compound; (2) Salts formed between organic compounds of sub-Chapters I to X or heading 29.42 are to be classified in the heading appropriate to the base or to the acid (including phenol- or enol- function compounds) from which they are formed, whichever occurs last in numerical order in the Chapter; and (3) Co-ordination compounds, other than products classifiable in sub-Chapter XI or heading 29.41, are to be classified in the heading which occurs last in numerical order in Chapter 29, among those appropriate to the fragments formed by "cleaving" of all metal bonds, other than metal- carbon bonds. (D) Metal alcoholates are to be classified in the same heading as the corresponding alcohols except in the case of ethanol (heading 29.05). (E) Halides of carboxylic acids are to be classified in the same heading as the corresponding acids. 6.- The compounds of headings 29.30 and 29.31 are organic compounds the molecules of which contain, in addition to atoms of hydrogen, oxygen or nitrogen, atoms of other non-metals or of metals (such as sulphur, arsenic or lead) directly linked to carbon atoms. Heading 29.30 (organo-sulphur compounds) and heading 29.31 (other organo-inorganic compounds) do not include sulphonated or halogenated derivatives (including compound derivatives) which, apart from hydrogen, oxygen and nitrogen, only have directly linked to carbon the atoms of sulphur or of a halogen which give them their nature of sulphonated or halogenated derivatives (or compound derivatives). 7.- Headings 29.32, 29.33 and 29.34 do not include epoxides with a three-membered ring, ketone peroxides, cyclic polymers of aldehydes or of thioaldehydes, anhydrides of polybasic carboxylic acids, cyclic esters of polyhydric alcohols or phenols with polybasic acids, or imides of polybasic acids. These provisions apply only when the ring-position hetero-atoms are those resulting solely from the cyclising function or functions here listed. 8.- For the purposes of heading 29.37 : (a) the term “hormones” includes hormone-releasing or hormone-stimulating factors, hormone inhibitors and hormone antagonists (anti-hormones); (b) the expression “used primarily as hormones” applies not only to hormone derivatives and structural analogues used primarily for their hormonal effect, but also to those derivatives and structural analogues used primarily as intermediates in the synthesis of products of this heading. Subheading Notes. 1.- Within any one heading of this Chapter, derivatives of a chemical compound (or group of chemical compounds) are to be classified in the same subheading as that compound (or group of compounds) provided that they are not more specifically covered by any other subheading and that there is no residual subheading named “Other” in the series of subheadings concerned. 2.- Note 3 to Chapter 29 does not apply to the subheadings of this Chapter.