In section C, the definitions of groups of chemical elements are as follows: Alkali metals: Li, Na, K, Rb, Cs, Fr Alkaline earth metals: Ca, Sr, Ba, Ra Lanthanides: elements with atomic numbers 57 to 71 inclusive Rare earths: Sc, Y, Lanthanides Actinides: elements with atomic numbers 89 to 103 inclusive Refractory metals: Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, W Halogens: F, Cl, Br, I, At Noble gases: He, Ne, Ar, Kr, Xe, Rn Platinum group: Os, Ir, Pt, Ru, Rh, Pd Noble metals: Ag, Au, Platinum group Light metals: alkali metals, alkaline earth metals, Be, Al, Mg Heavy metals: metals other than light metals Iron group: Fe, Co, Ni Non-metals: H, B, C, Si, N, P, O, S, Se, Te, noble gases, halogens Metals: elements other than non-metals Transition elements: elements with atomic numbers 21 to 30 inclusive, 39 to 48 inclusive, 57 to 80 inclusive, 89 upwards Section C covers: pure chemistry, which covers inorganic compounds, organic compounds, macromolecular compounds, and their methods of preparation; applied chemistry, which covers compositions containing the above compounds, such as: glass, ceramics, fertilisers, plastics compositions, paints, products of the petroleum industry. It also covers certain compositions on account of their having particular properties rendering them suitable for certain purposes, as in the case of explosives, dyestuffs, adhesives, lubricants, and detergents; certain marginal industries, such as the manufacture of coke and of solid or gaseous fuels, the production and refining of oils, fats and waxes, the fermentation industry (e.g., brewing and wine-making), the sugar industry; certain operations or treatments, which are either purely mechanical, e.g., the mechanical treatment of leather and skins, or partly mechanical, e.g., the treatment of water or the prevention of corrosion in general; metallurgy, ferrous or non-ferrous alloys. In the case of operations, treatments, products or articles having both a chemical and a non-chemical part or aspect, the general rule is that the chemical part or aspect is covered by section C. In some of these cases, the chemical part or aspect brings with it a non-chemical one, even though purely mechanical, because this latter aspect either is essential to the operation or treatment or constitutes an important element thereof. It has seemed, in fact, more logical not to dissociate the different parts or aspects of a coherent whole. This is the case for applied chemistry and for the industries, operations and treatments mentioned in Notes (1)(c), (d) and (e). For example, furnaces peculiar to the manufacture of glass are covered by class and not by class . There are, however, some exceptions in which the mechanical (or non-chemical) aspect carries with it the chemical aspect, for example: Certain extractive processes, in subclass ; The chemical purification of air, in subclass ; Chemical methods of fire-fighting, in subclass ; Chemical processes and apparatus, in class ; Impregnation of wood, in subclass ; Chemical methods of analysis or testing, in subclass ; Photographic materials and processes, in class , and, generally, the chemical treatment of textiles and the production of cellulose or paper, in section D. In still other cases, the pure chemical aspect is covered by section C and the applied chemical aspect by another section, such as A, B or F, e.g., the use of a substance or composition for: treatment of plants or animals, covered by subclass ; foodstuffs, covered by class ; ammunition or explosives, covered by class . When the chemical and mechanical aspects are so closely interlocked that a neat and simple division is not possible, or when certain mechanical processes follow as a natural or logical continuation of a chemical treatment, section C may cover, in addition to the chemical aspect, a part only of the mechanical aspect, e.g., after-treatment of artificial stone, covered by class . In this latter case, a note or a reference is usually given to make the position clear, even if sometimes the division is rather arbitrary. This subclass covers: compositions which are: explosive: compositions included are those containing both a fuel and sufficient oxidiser so that, upon initiation, they are capable of undergoing a chemical change of a relatively high rate of speed, resulting in the production of usable force for blasting, firearms, propelling missiles, or the like; thermic: compositions included have (i) a consumable fuel component which consists of any element which is a metal, B, Si, Se or Te, or mixtures, intercompounds, or hydrides thereof; and (ii) in combination an oxidant component which is either a metal oxide or a salt (organic or inorganic) capable of yielding a metal oxide on decomposition; fuels for rocket engines and intended for reaction with an oxidant, excluding air, in order to provide thrust for motive power purposes; for use in affecting the explosion environment, e.g. for neutralising the poisonous gases of explosives, for cooling the explosion gases, or the like; methods or apparatus for preparing or treating such compositions not otherwise provided for; methods of using single substances as explosives. In this subclass, the following term is used with the meaning indicated: "nitrated" covers compounds having a nitro group or a nitrate ester group. Methods or apparatus for preparing or treating such compositions are classified according to the particular components of the compositions. EXPLOSIVE OR THERMIC COMPOSITIONS Containing nitrated derivatives inorganic organic , Containing nitrides or fulminates , Containing chlorates or perchlorates Containing metal , Containing phosphorus Other compositions , Compositions defined by the structure or arrangement of the components , USE OF A SINGLE SUBSTANCE AS AN EXPLOSIVE MANUFACTURE In groups , in the absence of an indication to the contrary, a composition is classified in the last place that provides for an ingredient.