Crystal structure and infrared spectroscopy of MCl2·2CONH3 (M = Cu, Mn)

Crystals of MCl2·2CONH3 (M = Cu2+, Mn2+) are synthesized from low-temperature water-formamide solutions and studied by crystal optical, single crystal X-ray diffraction, and infrared spectroscopy methods. The crystal structures of CuCl2·2CONH3 and MnCl2·2CONH3 are solved by direct methods and refined in the P1triclinic space group, R1= 0.043 and 0.038 for 501 and 686 reflections with F0ÃΣ(F0) respectively. Unit cell parameters for Cu and Mn salts are: a = 3.705(1) Å and 3.685(1) Å, b = 7.049(2) Å and 7.136(2) Å, c = 7.375(2) Å and 7.779(2) Å, 6h =113.57(3)² and 117.17(2)², β = 96.17(3)² and 95.35(2)², γ = 94.85(3)² and 92.23(2)² respectively, Z= 1. In the studied crystal structures, MCl4O2 octahedra share Cl-Cl edges and form chains along the [100] direction. This direction corresponds to a morphological elongation of the obtained crystals and orientation of the maximum refractive index. The FT infrared spectra obtained in a range from 4000 cm−1 to 300 cm−1 are very close to the spectrum of liquid formamide, but exhibit better resolution of absorption bands.