Structures and formation mechanism of potassium cyanide clusters

Formation of potassium cyanide clusters in the direct laser vaporization of K3[Fe(CN)6] was studied by use of a TOF mass spectrometer. It was found that the positive cluster ions are due to [K(KCN)n]+, n = 0–37, in which magic numbers are n = 4, 13, 22, 37, whereas the negative cluster ions were assigned to [(KCN)nCN]−, n = 0–13, where magic numbers are n = 4, 13. These magic numbers are identical with those of alkali-halide clusters. This indicates that they have the structures 1 × 3 × 3 (n = 4), 3 × 3 × 3 (n = 13), 3 × 3 × 5 (n = 22), 3 × 5 × 5 (n = 37) as those of alkali-halide clusters. Thus the formation process of potassium cyanide clusters should go along the growth course of the rock salt structure.