Synthesis, thermal behaviour and crystal structure of RbSrP3O9•3 H2O

Rubidium strontium cyclo-triphosphate trihydrate, RbSrP3O9.3H(2)O, was synthesized by reaction between cyclo-triphosphoric acid H3P3O9 and rubidium and strontium carbonates. It crystallizes in the othorhombic system, space group Pnma, with a = 9.120(1) Angstrom, b = 8.141(1) Angstrom, c = 15.234(1) Angstrom V = 1 131.1(3) Angstrom (3), Z = 4. Crystal structure determination from single crystal data collected at 300 K shows that the P3O9 groups exhibit Cs symmetry and are not connected to each other. Rubidium (distorted octahedron) and strontium (distorted square antiprism) are coordinated by oxygen and water molecules yielding the formation of infinite chains interconnected to each other and to the P3O9 groups. The IR valence vibration bands of the P3O9 cycle have been identified in the domain 1400-650 cm(-1) and related to the structural results. After water loss, the anhydrous phase crystallizes from an intermediate amorphous phase and further decomposes into Rb2SrP4O12 and Srp(2)O(6). (C) 2000 Academie des sciences/Editions scientifiques et medicales Elsevier SAS.