Tricapped trigonal prismatic geometry

U pm) as would be required for tricapped trigonal prismatic geometry the bonding B-B contacts are all within the normal range. 

In contrast to the monoclinic tris-malonato complexes, M2(OOCCH2COO)s 8 H2O (M=Nd) which contain nonacoordinated lanthanide ions in a monocapped square antiprismatic polyhedron, the orthorhombic tris-malonates Pnma) have a tricapped trigonal prismatic geometry for the coordination polyhedron. A rep-... 

Figure 1. The tricapped trigonal prismatic geometry of the [ReHg]= anion (18)...

High coordination number hydrides are not uncommon seven-, eight- and nine-coordinate hydrides so far seem to have been found only in pentagonal biprismatic, dodecahedral and tricapped trigonal prismatic geometries, respectively. 

The tricapped trigonally prismatic coordination of europium in Eu(terpy)3(C104)3 is probably the first example of 9-coordination involving nitrogen donors [150], Tricapped trigonal prismatic geometry is present in some simple hydrated compounds [165,166] such as Nd(H20)9(Br03>3 and M OMC H SC Xq, where M = Pr, Er, Ho, V. The structure of [Yb(DPC)3]3 is shown in Fig. 5.26. 

A coordination number of 9 with a tricapped trigonal prismatic geometry appears to be common as in [Ln( HiO lXt. 

Unlike the exclusively 6-coordinate iron(iii) siderophore complexes, higher coordination numbers are possible with plutonium the complex of Pu" with desferrioxamine E (DEE a hexadentate iron-binding siderophore ligand) has shown it to contain 9-coordinate [Pu(dfe)(H20)3]+ ions with a tricapped trigonal prismatic geometry (Figure 11.13). 

The trivalent plutonium aquo ion, [Pu(H20)9] +, has been crystallized with nine H2O ligands in a tricapped trigonal prismatic geometry." ... 

Figure 5 Crystal structure of [Pu(H20)9][CF3S03]3, showing Pu aqua with ideal tricapped trigonal prismatic geometry (Matonic, Scott et al. Inorg. Chem. 2000, 40, 2638).

Figure 9.1 The Tricapped Trigonal Prismatic Geometry of the [ReHJ Anion (a) and the Central Core of HgRe2(PEt2ph)4 (b).

The actinide trichlorides are hygroscopic and water soluble and melt between 1030 and 1110 K. They can be obtained by reaction of the metal hydride with HCl at elevated temperatures or by the reaction of CCU with An(OH)3. With the larger actinide(ni) ions, the crystal structures of the trichlorides show nine chlorine atoms arranged in a tricapped trigonal prismatic geometry. As the atomic number increases, the three actinide to facecapping-chlorine distances increase relative to the other six chlorines. At caUfomium, a second form of CfCb has eight coordination. 

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