On the CN−⋯K coordination modes in Kn[M6−n(CN)6]·xH2O: first evidence of CN−⋯K electron-deficient bonding

Abstract

The occurrence of electron-deficient bonding (3c–2e or 4c–2e) between the CN⁻ ligand N end and K⁺ is reported for the structures of K_n[M⁶⁻ⁿ(CN)₆]·xH₂O. The atypical N-bipodal and N-tripodal coordination CN⁻···K⁺ agrees with these bonding models.