[Ni<i>En</i><sub>3</sub>]WO<sub>4</sub>. Crystal structural features of the phase transition at 269 K
The synthesis method for [Ni En 3]WO4 complex salt is described. Data of single crystal X-ray diffraction at 115 K are: space group P -3, a = 15.9633(5) Å, c = 9.9446(4) Å, V = 2194.6(1) Å3, Z = 6, dx = 2.210 g/cm3, Ni-N is 2.120(2)-2.149(2) Å, ∠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 -31 c, a = 9.2641(3) Å, c = 9.9817(3) Å, V = 741.89(4) Å3, Z = 2, dx = 2.179 g/cm3, Ni-N is 2.128(2) Å, ∠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.