Angewandte Chemie International Edition
© WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Cover Picture (Angew. Chem. Int. Ed. Engl. 6/1989)
The cover picture shows part of the structure of the new molybdenum phosphate [Et4N]6[Na14Mo24P17O97(OH)31]·xH2O. The most interesting feature of this, at first sight, complicated molecule is the oxidation state of the molybdenum atoms (Mov) as well as the finding that an H3PO4 molecule (green tetrahedron in the center of the picture) lies at the center of a cavity formed by [Mo6P4O24(OH)7]5⊖ anions and Na⊕ cations. In addition to the H3PO4 molecule, the cluster anion pictured, [Na12Mo24P17O97(OH)31]8⊖, consists of four[Mo6P4O24(OH)7]5⊖ ions, each composed of six MoO6 octahedra (light and dark blue) and four phosphate groups (green tetrahedra – one HPO42⊖ and three H2PO4⊖) units. The MoO6 tetrahedra each share edges with two neighboring octahedra. Red, O atoms; yellow, Na atoms; green, P atoms; blue, Mo atoms. For clarity, the MoO6 octahedra are not fully shown. Further details on this H3PO4 “inclusion complex” are reported by R. C. Haushalter et al. on p. 743 ff.