Crystal structures of the microporous compounds M6(V2O3)2(VO)2(PO4)4(HyP2−xVxO7) with M=K+, Tl

• Published in: The international journal of inorganic materials 2001-07, Vol.3 (4-5), p.341-345
• Main Authors: Le Fur, E, de Villars, B, Tortelier, J, Pivan, J.Y
• Format: Article
• Language: English
• Subjects: Crystal structures; Hydrothermal synthesis; Potassium and thallium vanadium phosphates
• ISSN: 1466-6049; 1466-6049
• DOI: 10.1016/S1466-6049(01)00032-0

Brownish compounds of M6(V2O3)2(VO)2(PO4)4(HyP2−xVxO7) were prepared hydrothermally and were found to crystallize in the orthorhombic symmetry (space group Pmn21) with cell parameters a=13.5043(7) Å, b=6.9895(2) Å, c=14.1962(8) Å (K+); a=13.5472(5), b=7.1765(1) Å, c=14.3812(3) (Tl+). Their structures were solved from single crystal X-ray diffraction down to the reliability factors R1(Fo)=0.048 (K+), 0.042 (Tl+). The three dimensional network consists of infinite [VO3] chains of trans sharing distorted octahedra and dimers [V2O6] built up from the linkage of square planar pyramids [VO5]. The chains and the dimers are assembled through PO4 bridges. In addition, disordered and partially substituted (HyP2−xVxO7) groups that run along b ensure the connectivity between adjacent [V2O6] units. The resulting host lattice consists of intersecting tunnels in which the univalent cations are located.