| Abstrakt: |
Three phosphates, MIBaIn2(PO4)3with MI=Na, K, Cs, isostructural to the langbeinite structure, have been studied from powder diffraction data collected with monochromatic radiation obtained from a conventional X-ray source. Precise powder data are reported, as well as cell parameters, i.e., a=10.026 08(9) ?, a=10.121 57(13) ? and a=10.226 94(9) ? for MI=Na, K and Cs, respectively. A Rietveld refinement has been carried out (space group P213), with final RFfactors, 0.061, 0.041 and 0.027, and Rwpfactors, 0.196, 0.142 and 0.129, for MI=Na, K and Cs, respectively. There are two octahedrally coordinated In3+ions in the asymmetric unit and the final refinements suggest disorder on the two sites of the MI/Ba sublattice. |
