Single crystals of monoclinic ce-VOHPO4.2H20, ce-oxovanadium(IV) hydrogen phosphate dihydrate, were synthesized by hydrothermal reaction. The structure was refined with good accuracy (R = 0.018) and the results are compared with those of an earlier structure determination from X-ray powder data [Le Bail et al. (1989). Eur. J. Solid State Inorg. Chem. 26,[419][420][421][422][423][424][425][426]. Significant differences in bond lengths were found. The structure consists of vanadyl hydrogen phosphate layers running along [ 100]. The layers are connected via hydrogen bonds.
Source of materialA mixture of 12 ml 85% H3PO4,32 ml H20,15 g oxalic acid and 14.5 g V2O5 was boiled with stirring for 6 hours. The dark blue solution was filled in teflon lined and sealed autoclave and kept at 338 Κ for two weeks. The crystals was filtered off, washed with water and dried at 323 K.
DiscussionVanadium(IV)hydrogenphosphates play an important role in the process of selective oxidation of the paraffin n-butan to MS A [ 1 ]. We redetermined the structure of VOHPO4 · 4H2O by single crystal structure analysis. The results confirm with the structure of Leonowitz [2], the structure data were improved and the positions of hydrogen atoms were estimated. The structure of VOHPO4 · 4H20 consists of VOe octahedra and PC>4-tetrahedra forming double chains along a axis. The VOó octahedron is axial surrounded by three phosphate oxygen and a water oxygen. The bond distances to the phosphate oxygens are nearly 2.00 Â and the distance to the water oxygen is nearly 2.06 À.On the opposite side of the vanadyl oxygen is a second water molecule coordinated. The bond distances are nearly 1.59 Á for the vanadyl oxygen and 2.25 Â for the coordinated water oxygen. VOó-octahedrons and PO4 tetrahedrons form double chains along the a axis. In the single chain alternate VOó octahedra and PO4 tetrahedra. Every V06 octahedron shares vertices with an PO4 tetrahedron of the neighbour chain and every PO4 tetrahedron with an VOÓ octahedron of the neighbour chain. The double chains are translated in the [011] direction to form a layer (Fig.). The double chains are linked in the layer via hydrogen bonds. The hydrogen bond is formed by a hydrogen of a axial vanadium coordinated water to a oxygen linking a VOó octahedron and a PO4-tetrahedron. The layers connect via two kinds of hydrogen bonds. The hydrogen of equatorial coordinated water of V(2) bonds to the oxygen of equatorial coordinated water of V( 1 ) and the hydrogen of P(2)-OH group bonds to the oxygen of the P (
structure structure (solids and liquids) D 2000 25 -021 Redetermination of Monoclinic VOHPO 4 ·2H 2 O. -Single crystals of the title compound are grown hydrothermally from V 2 O 5 in aq. H 3 PO 4 in the presence of oxalic acid (autoclave, 363 K, 14 d). α-VOHPO 4 ·2H 2 O crystallizes in the monoclinic space group P2 1 /c with Z = 4. The new single crystal XRD data show significant differences in bond lengths when compared with previous powder data. -(WORZALA, H.; GOETZE, T.; FRATZKY, D.; MEISEL, M.; Acta Crystallogr., Sect. C: Cryst.
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.