Synthesis, thermal behaviour and crystal structure of RbSrP3O9 center dot 3 H2O

Rubidium strontium cyclo-triphosphate trihydrate, RbSrP3O9.3H(2)O, was synt hesized by reaction between cyclo-triphosphoric acid H3P3O9 and rubidium an d strontium carbonates. It crystallizes in the othorhombic system, space gr oup 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 determinatio n from single crystal data collected at 300 K shows that the P3O9 groups ex hibit Cs symmetry and are not connected to each other. Rubidium (distorted octahedron) and strontium (distorted square antiprism) are coordinated by o xygen and water molecules yielding the formation of infinite chains interco nnected to each other and to the P3O9 groups. The IR valence vibration band s 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 cr ystallizes from an intermediate amorphous phase and further decomposes into Rb2SrP4O12 and Srp(2)O(6). (C) 2000 Academie des sciences/Editions scienti fiques et medicales Elsevier SAS.