[NiEn3]WO4. Crystal Structural Features Of The Phase Transition At 269 K

The synthesis method for [NiEn3]WO4 complex salt is described. Data of single crystal X-ray diffraction at 115 K are: space group \(p\bar 3\), a = 15.9633(5) A, c = 9.9446(4) A, V = 2194.6(1) A3, Z = 6, dx = 2.210 g/cm3, Ni–N is 2.120(2)-2.149(2) A, ∠N–Ni–N is 80.69(7)-82.28(7)°. From the differential scanning calorimetry data it is found that a phase transition occurs at 269 K. The crystal structural characteristics at 298 K are as follows: space group \(p\bar 31c\), a = 9.2641(3) A, c = 9.9817(3) A, V = 741.89(4) A3, Z = 2, dx = 2.179 g/cm3, Ni–N is 2.128(2) A, ∠N–Ni–N is 81.05(12)°. The phase transition is shown to correspond to the disordering of tungstate anions over three positions. The comparative analysis of N–H…O and C–H…O interionic contacts is performed.