title: Rietveld refinement of Ba(5)(AsO(4))(3)Cl from high-resolution synchrotron data.
abstract: The apatite-type compound Ba(5)(AsO(4))(3)Cl, penta-barium tris-[arsenate(V)] chloride, has been synthesized by ion exchange at high temperature from a synthetic sample of mimetite (Pb(5)(AsO(4))(3)Cl) with BaCO(3) as a by-product. The results of the Rietveld refinement, based on high resolution synchrotron X-ray powder diffraction data, show that the title compound crystallizes in the same structure as other halogenoapatites with general formula A(5)(YO(4))(3)X (A = divalent cation, Y = penta-valent cation, X = Cl, Br) in space group P6(3)/m. The structure consists of isolated tetra-hedral AsO(4) (3-) anions (m symmetry), separated by two crystallographically independent Ba(2+) cations that are located on mirror planes and threefold rotation axes, respectively. The Cl(-) anions are at the 2b sites ( symmetry) and are located in the channels of the structure.
authors.forename: Anthony M T
authors.initials: AM
authors.lastname: Bell
authors.forename: C Michael B
authors.initials: CM
authors.lastname: Henderson
authors.forename: Richard F
authors.initials: RF
authors.lastname: Wendlandt
authors.forename: Wendy J
authors.initials: WJ
authors.lastname: Harrison