Synthesis and crystal structure of a new potassium-gadolinium cyclotetraphosphate, KGdP4O12

The chemical preparation, crystal structure, and infrared absorption spectrum are given for a new cyclotetraphosphate, KGdP4O12. X-ray investigations showed that the newly synthesized compound crystallizes in a monoclinic structure, space group C2/c with the following unit-cell dimensions: a = 7.875(1), b = 12.431(2), c = 10.537(2) Angstrom, beta = 110.94(1)degrees, V = 963.4(3) Angstrom(3), Z = 4, and rho = 3.532 g cm(-3) The structure was solved from 1390 independent reflections with R-1= 2.99 and WR2 = 7.37%, refined with 84 parameters. As in all atomic arrangements, we observe the formation of an infinite network of P4O124- cyclotetraphosphate anions connected with GdO8 polyhedra to form a three-dimensional framework which delimits interesting tunnels where the K+ cations are located. In this structure, the P4O12 ring develops around an inversion center. The reported IR study, recorded at room temperature in the frequency range 400-4000 cm(-1), shows some characteristics bands of cyclotetraphosphates.