Cu(VO)(SeO3)2 (A) and (B) Forms: Synthesis and Crystal Structures of New Copper(II)–Vanadyl(IV) Diselenites

Two forms of copper(II) vanadyl(IV) diselenite CuVO(SeO3)2 have been synthesized by solid state reaction. The form (A) belongs to the monoclinic system space group P21/c with a=7.983(1) ?, b=8.877(2) ?, c=8.437(2) ?, and beta=100.62 (2)°. It is a layered structure built up of CuO6 and VO6 octahedra associated, respectively, by pairs via edge sharing which are making [Cu2O10] and [V2O10] dimers. These dimers are building a layer [CuVO7]n upon which are fixed the selenium (IV) cations. The lone pairs of the selenium (IV) are packed in a double layer perpendicular to the [001] direction. Form (B) crystallizes in the orthorhombic system, space group Pnma with a=7.071(2) ?, b=8.223(2) ?, and c=9.500(2) ?. The structure also exhibits dimers associated via edge and corner sharing along the [100] and [010] directions, which build up layers parallel to the (001) plane; they are held together by Se–O bonds. The connection via V–O–Cu induces a local order that does not respect the three-dimensional order of the network.