Cover Picture (Angew. Chem. Int. Ed. Engl. 6/1989)

The cover picture shows part of the structure of the new molybdenum phosphate [Et 4 N] 6 [Na 14 Mo 24 P 17 O 97 (OH) 31 ]· x H 2 O. The most interesting feature of this, at first sight, complicated molecule is the oxidation state of the molybdenum atoms (Mo v ) as well as the finding that an H 3 PO 4 molecule (green tetrahedron in the center of the picture) lies at the center of a cavity formed by [Mo 6 P 4 O 24 (OH) 7 ] 5⊖ anions and Na ⊕ cations. In addition to the H 3 PO 4 molecule, the cluster anion pictured, [Na 12 Mo 24 P 17 O 97 (OH) 31 ] 8⊖ , consists of four[Mo 6 P 4 O 24 (OH) 7 ] 5⊖ ions, each composed of six MoO 6 octahedra (light and dark blue) and four phosphate groups (green tetrahedra – one HPO   4 2⊖and three H 2 PO   4 ⊖ ) units. The MoO 6 tetrahedra each share edges with two neighboring octahedra. Red, O atoms; yellow, Na atoms; green, P atoms; blue, Mo atoms. For clarity, the MoO 6 octahedra are not fully shown. Further details on this H 3 PO 4 “inclusion complex” are reported by R. C. Haushalter et al. on p. 743 ff.