Tricapped trigonal prismatic molecules

The Gd + complex of a diamide (22) has an octadentate ligand in a nine-coordinate tricapped trigonal prismatic molecule with one coordinated water molecule. ... 

It was only in 1995 that the first structure of a hydrated salt of scandium containing only water molecules in its coordination sphere was reported. Refluxing scandium oxide with triflic acid leads to the isolation of hydrated scandium triflate Sc(03SCF3)3 9H20. It is isomorphous with the hydrated lanthanide triflates, containing tricapped trigonally prismatic coordinate scandium in the [Sc(H20)g] ions, with Sc—O (vertices) = 2.171(9) A and Sc—O (face capped) 2.47(2) A. 

Hydroxide, aqua, and hydrates. From the similar absorption spectra of Am in aqueous solution, AmCls, and in Lads, and the linear relationship between the decay rate of the americium fluorescence and the number of inner-sphere water molecules, it has been concluded that Am " is coordinated by nine inner-sphere water molecules. Similarly, the hydration number for the Cm ion has been estimated to be nine on the basis of fluorescence lifetimes. EXAFS studies of aqueous Am and Cm, however, have suggested coordination numbers closer to 10. " EXAFS investigation of Cf " " in aqueous solution indicates a coordination number of 8.5 ( 1.5), with a Cf—O distances of 2.41 0.02 A. This coordination number was confirmed for Am in the solid state by isolation of single crystals of the triflate salt of nonaqua complex, which contains a tricapped, trigonal prismatic cation that is isostructural with the analogous Pu" compound. ... 

For solid lanthanide salts in which the cation coordination sphere is saturated with nine water molecules, the oxygen atoms form a tricapped trigonal prismatic structure surrounding the cation. Within an isostructural series, the changes in bond length are directly proportional to the changes in ionic radius. No evidence has been found in solids for a change in the hydration number when the primary coordination sphere is... 

Fig. 13.13 The family of B X (X = Cl, Br, I) molecules possess cluster structures, (a) B4CI4 has a tetrahedral core, (b) BgClg possesses a dodecahedral cluster core and (c) B9Br9 has a tricapped trigonal prismatic core. Colour code B, blue Cl, green Br, gold.

La(N03)2(dipy)(0H2)4][N03] -2dipy is crystallized in P2i/c with one symmetry unique formula unit (Z = 4) (Fig. 2.8). The La " cation is coordinated by four water molecules, one unidentate dipyridyl ligand, and two bidentate nitrate ions in a tricapped trigonal prismatic arrangement (Fig. 2.9). This complex has a net charge... 

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