Аннотация:Single-crystals of manganese hydroxide hydrogen vanadate divanadate, Mn6.75(OH)3H1.20(VO4)4-2z(V2O7)z (z = 0.15), have been synthesized hydrothermally. Its hexagonal crystal structure, sp. gr. P63mc, related to mineral ellenbergerite, has been determined by the single-crystal X-ray diffraction. It features a three-dimensional framework of vertex- and face-sharing Mn2+ - centered octahedra with defective Mn2+- octahedral chains and disordered V2O7, HVO4 and H2VO4 groups located in hexagonal and triangular type channels. The presence of these groups has been confirmed by the Fourier transform infrared spectroscopy. According to magnetization and specific heat data, Mn6.75(OH)3H1.20(VO4)4-2z(V2O7)z (z = 0.15) experiences ordering into canted antiferromagnetic state at TN = 42.5 K.
