On the crystal structures of the cyano complexes [Co(NH3)(6)][Fe(CN)(6)]1,[Co(NH3)(6)](2)[Ni(CN)(4)](3) center dot 2H2O, and [Cu(en)(2)][Ni(CN)(4)]

Of the three title compounds X-ray structure determinations were performed with single crystals. [Co(NH3)(6)][Fe(CN)(6)] (a = 1098.6(6), c = 1084.6(6) pm, R3, Z = 3) crystallizes with the CsCl-like [Co(NH3)(6)][Co(CN)(6)] typ e structure. [Co(NH3)(6)](2)[Ni(CN)(4)](3) (.) 2H(2)O (a = 805.7(5), b = 85 5.7(5), c = 1205.3(7)pm, alpha = 86.32(3), beta = 100.13(3), gamma = 90.54( 3)degrees, P1, Z = 1) exhibits a related cation lattice, the one cavity of which is occupied by one anion and 2H(2)O, whereas the other contains two a nions parallel to each other with distance Ni...Ni: 423,3 pm. For [Cu(en)(2 )][Ni(CN)(4)] (a = 650.5(3), b = 729.0(3), c = 796.5(4) pm, alpha = 106.67( 2), beta = 91.46(3), gamma = 106.96(2)degrees, P1, Z = 1) the results of a structure determination published earlier have been confirmed. The compound is weakly paramagnetic and obeys the Curie-Weiss law in the range T < 100 K. The distances within the complex ions of the compounds investigated (Co- N: 195.7 and 196.4 pm, Ni-C: 186.4 and 186.9 pm, resp.) and their hydrogen bridge relations are discussed.