| Abstract: | The infrared and diffuse reflectance spectra in the visible and ultraviolet region of the following compounds have been measured: Ni(CN)2, 2 H2O, Ni(CN)2, 1½ H2O, Ni(CN)2, NH3, ¼ H2O, Ni(CN)2, NH3, R (R = C6H6, C6H5NH2, C6H5OH). The structural units of these compounds are shown to be the square planar NiC4] and the pseudo-octahedral NiN4L2]-group (L = H2O, NH3) with Ni-C-N-Ni-bridges. Additional water is present as zeolitic water. The magnetic data give a 1:1 relation of the paramagnetic pseudo-octahedral to the diamagnetic square planar co-ordination polyhedra. The nitrogen of the cyanide ion is close to ammonia in the spectrochemical as well as in the nephelauxetic series, the values of Dq and B being ?1000 and ?900 cm?1 respectively. The absorption bands of the aromatic molecules in the clathrates are shifted towards lower wave numbers compared to the corresponding solution spectra. |
