Tricapped trigonal prisms nine-coordinate compounds

A second form of neodymium malonate, Nd2(mal)3-6H20, also exists (Hansson, 1973c). In this compound each neodymium is also nine-coordinate, surrounded by six carboxylate and three wat er oxygen atoms, and the coordination polyhedron is intermediate between the distorted capped square antiprism and the distorted tricapped trigonal prism. 

In the structures of compounds of the type M3UF7 the seven F atoms are statistically distributed over fluorite lattice sites.153 The nine-coordinate thorium atom in (NH ThFg is surrounded by a distorted tricapped trigonal prismatic array of fluorine atoms, with the prisms sharing edges to form chains, whereas the uranium(IV) compound contains discrete dodeca-hedrally coordinated [UF8]4 ions. The protactinium(IV), neptunium(IV) and plutonium(IV) analogues are isostructural with the uranium compound.154... 

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