Nitridochromate(IV): LiSr₂[CrN₃]

The quaternary nitridochromate(IV) LiSr2[CrN3] crystallizes in a new structure type with the non-centrosymmetric space group P21 (no. 4) with a = 5.5685(7) Å, b = 5.3828(8) Å, c = 7.5381(1) Å, and β = 92.291(8)°. Predominant structural features of the compound are slightly nonplanar trigonal units [CrN3]5–, which are connected by three-fold coordinated lithium to form slabs in the (001) plane. Shorter Cr–N bond lengths in comparison with reported nitridochromates(III), as well as diamagnetic behavior and vibrational spectroscopy data indicate Cr(IV), which is in a good agreement with the charge balance. According to electronic structure calculations, the compound is a semiconductor with a band gap of 1.19 eV