由金属氧化物制成的金属氢氧化物是否属于 REACH 法规附件 V 第 6 点中的注册豁免范围？

由金属氧化物制成的金属氢氧化物是否属于 REACH 法规附件 V 第 6 点中的注册豁免范围？

Is a metal hydroxide manufactured from the metal oxide covered by the exemption from registration in Annex V, point 6 of the REACH Regulation?

根据 REACH 法规附件 V 第 6 点，物质的水合物或物质与水结合形成的水合离子无需注册，前提是该物质（即无水形式）已由其制造商或进口商注册。物质的水合物的特征在于水分子通过分子相互作用（特别是氢键）与该物质的其他分子或离子相连。就附件 V 而言，化合物的水合物和无水形式（无水）应被视为同一种物质（例如 CuSO4.5H2O 和 CuSO4）。相反，金属氢氧化物（例如 Ca(OH)2）和金属氧化物（例如 CaO）不能被视为同一种物质，因为无论制造工艺如何，这两种物质的结构都不同。氢氧化物的形成涉及新共价键的形成，这与仅涉及弱分子间键的水合物的形成不同。因此，由金属氧化物制成的金属氢氧化物不属于附件五第 6 点中的注册豁免范围。

According to Annex V, point 6 of the REACH Regulation hydrates of a substance or hydrated ions, formed by association of a substance with water are exempted from registration, provided that the substance (i.e. the anhydrous form) has been registered by its manufacturer or importer.   Hydrates of a substance are characterised by the fact that water molecules are linked by molecular interactions, in particular by hydrogen bonds, to other molecules or ions of the substance. For the purposes of Annex V, hydrates and water free forms (anhydrous) of compounds shall be regarded as the same substance (e.g. CuSO4.5H2O and CuSO4).   In contrast, a metal hydroxide (e.g. Ca(OH)2) and a metal oxide (e.g. CaO) cannot be regarded as the same substance as both substances have different structures, regardless of the manufacturing process. The formation of the hydroxide involves forming new covalent bonds, which is different from forming a hydrate which only involves weak intermolecular bonds. Therefore a metal hydroxide manufactured from the metal oxide is not covered by the exemption from registration in Annex V, point 6.