Abstract
Single crystals of the novel phosphate (Cd,Co)5(HPO4)2(PO4)2.4H2O have been elaborated under mild hydrothermal conditions and analyzed by single-crystal X-ray diffraction. The title compound crystallizes in the Hureaulite-type structure (space group C2/c, a = 17.5744(9) Å, b = 9.0723(5) Å, c = 9.4866(5) Å, β = 96.67(3)°, V = 1502.3(1) Å3 and Z = 4). This structure exhibits a cations positional disorder at two sites. The first one is located on the special Wyckoff position 4e(2) and is fully filled by a mixture of Cd(2)2+/Co(2)2+ with a respective occupancy ratio of 0.34/0.66. The second one is located on the general position 8f, fully occupied by both Cd(1)2+/Co(1)2+. The principal building units are more or less distorted [(Cd(1)/Co(1))O5(OH2)], [(Cd(2)/Co(2))O6], and [Co(3)O4(OH2)2] octahedra with two kinds of regular PO4 and HPO4 tetrahedra. This crystal structure results from octahedral pentameric units M5IIO16(OH2)6 made up of edge-sharing extending parallel to [001] direction. These adjacent entities are interconnected and also linked to each other by the connecting PO4 and HPO4 units via common corners so as to build a three-dimensional framework delimiting large holes along the c-axis hosting the water molecules. Bond-valence-sum (BVS) and charge-distribution (CD) methods were applied to validate the suggested structural model.
doi: 10.17756/nwj.2023-s2-064
Citation: El Alami C, Khmiyas J, Hadouchi M, Assani A, Saadi M, et al. 2023. Elaboration, Characterization and Structural Study of a Novel Phosphate (Cd,Co)5(HPO4)2(PO4)2.4H2O with the Hureaulite Structure Type. NanoWorld J 9(S2): S378-S382.
Download Citation (XML)
