The crystal structure of KAu(CN)2

Abstract

KAu(CN)2 is rhombohedral, space group R3, with a =9.74 A and a =43.9 . The structure is similar to that of KAg(CN)~ and consists of layers of linear Au(CN)~-ions alternating with layers of K+ ions. However, the stacking of the layers differs in the two compounds, so that KAg(CN)~ is hexagonal and KAu(CN)~ is rhombohedral. A refinement of the structure was made by least-squares analysis of counter data. The Au-C bond is 2.12_+0.14 J~, the C-N bond is 1-17_+0.20 A and the average K-N distance is 2.78/~. Twinned crystals of KAu(C~I)~ often occur and the nature of this twinning is discussed in detail.