NaAl(MoO4)2: a rare structure type among layered yavapaiite-relatedAM(XO4)2compounds

Abstract

NaAl(MoO4)2, sodium aluminium dimolybdate(VI), represents a rare pseudo-orthorhombic structure type among AM(XO4)2 compounds with yavapaiite-related sheet structures. It is isostructural with NaFe(MoO4)2. Infinite (001) sheets composed of AlO6 octahedra, corner-linked to MoO4 tetrahedra, are separated by eight-coordinated Na atoms. Average Na—O, Al—O and Mo—O bond lengths are 2.648, 1.890, and 1.762 A, respectively. All atoms are on general positions except for Na and Al (both of which have site symmetry \overline 1).