Abstract
Four new Bi(III) phosphates, K_6Bi_(13)(PO_4)_(15), K_5Bi(P_2O_7)_2, and A_5Bi_5(PO_4)_4(P_2O_7)_2 (A= K, Rb) with the different condensed P-0 groups have been successfully synthesized via the solid-state reactions. The single crystals X-ray diffractions show that they crystallize in the different space groups (K_6Bi_(13)(PO_4)_(15): C2; K_5Bi(P_2O_7)_2: P1; K_5Bi_5(PO_4)_4(P_2O_7)_2 and Rb_5Bi_5(PO_4)_4(P_2O_7)_2: P2_1/c). The structure of K_6Bi_(13)(PO_4)_(15) can be described as a three-dimensional (3D) network composed of the Bi-0 polyhedra and PO_4 tetrahedra with K atoms filling in the space to balance the residual charges. K_5Bi(P_2O_7)_2 features 2D [BiP_4O_(14)]_∞, layers built by the BiO_6 oc-tahedra and P_2O_7 dimers and the adjacent [BiP_4O_(14)]_∞ layers are bridged by the K atoms. A_5Bi_5(PO_4)_4(P_2O_7)_2 (A = K, Rb) contain two different condensed P-0 groups, PO_4 tetrahedra and P_2O_7 dimers, which are connected by Bi-0 polyhedra to construct the complicated 3D framework with K/Rb atoms located in the tunnels. Note that, the compounds that simultaneously contain two different types of P-0 groups are still rare in phosphates. Detailed structural comparisons of Bi~(3+)-containing phosphates indicate that the Bi/P ratios have a significant effect on the condensed degrees of PO_4 groups. Furthermore, TG-DSC, IR, UV-Vis-NIR diffuse reflectance spectra and SHG test for title compounds have also been reported.
NSTL
Elsevier