Die Kristallstrukturbestimmung des monoklinen, basischen Kupfernitrates Cu4(NO3)2 (OH)6 II

Abstract The complete crystal structure of monoclinic basic copper nitrate was determined by means of Patterson ‐, trial and error‐ and Fourier ‐methods. The lattice constants, space group and atomic coordinates are tabulated on p. 383. The Cu atoms form a pseudohexagonal net (001) with CuCu = 3,03 resp. 3,17 Å. Each Cu I is surrounded by 2 OH I , 2 OH II and 2 O I (of NO 3 ‐groups) at the distances 2,00, 2,08 and 2,35 Å (deformed octahedron); each Cu II in an analogous way by 4 OH II , 1 O I and 1 OH I at 2,05, 2,18 and 2,27 Å. The structure shows layers of octahedra (of the C 6‐type) CuX 6/3 = CuX 2 (X = OH I , OH II ,O I ). The distance OH II O II is 2,46–2,60 Å and is interpreted as a hydrogen bond OH II ⃛ O II . The layers of octahedra are linked together by these H‐bonds via the NO 3 ‐groups, which are nearly normal to the layer planes. Contrary to many layer structures this compound is optically positive, apparently a result of the position of the nitrate groups. The crystal structure is isotypical with the basic copper bromide.