Is the ground-state structure of (KCl)0.25(KCN)0.75a noncubic orientational glass?

Constant-pressure molecular dynamics has been used to study the mixed crystal (KCl${)}_{0.25}$(KCN${)}_{0.75}$. On cooling from the high-temperature cubic rotator phase, this system undergoes a transition to a ground-state monoclinic structure, with indication of an intermediate rhombohedral phase. At low temperature, the ${\mathrm{CN}}^{\mathrm{-}}$ quadrupoles freeze into a state with disordered orientations, thus suggesting the formation of a noncubic orientational glass phase. The orientational freezing is accompanied by anomalous diffraction profiles.