CRYSTAL-STRUCTURE OF CDSR(PO3)4 POLYPHOSPHATE

Crystals of the polyphosphate CdSr(PO3)4 , isostructural with CdBa(PO3)4, have been obtained with flux method, The parameter values of the monoclinic cell (P2(1)/n) are : a = 14.823(5)angstrom, b = 9.046(2)angstrom, c = 7.088(2)angstrom et beta = 91.07-degrees-(2). 1074 observed reflexions have been used to resolve the crystal structure. The final agreement factors are R = 0.037 and Rw = 0.049. The lattice contains infinit and meandering (PO3)infinity chains along the c direction with a period of four PO4 tetrahedra. These chains are holded together with CdO6 and SrO8 so as to build a three dimensionnal framework P-O distance values are varying from 1.467(8) to 1.603(7) angstrom. Cadmium atoms are located in octahedral polyhedra of oxygen ions ; Cd-O distances are ranging between 2.269(7) and 2.340(7)angstrom. Sr2+ ions have eight neighbouring oxygen atoms with Sr-O mean bond value 2.653(8)angstrom.