Stereochemistry of Compounds with Coordination Number Ten

Abstract

The stereochemistry of ten-coordinate rare-earth and transition-metal compounds is studied from the point of view of continuous shape measures (CShM) and derived tools. A total of 19 ideal ten-vertex polyhedra belonging to 12 different symmetry point groups have been considered, from which nine are retained for the description of the stereochemistries of all studied compounds. The structures of the coordination spheres are analyzed by families, according to the denticity and topology of the ligands. Some ligand topologies are seen to consistently favor usually neglected ideal polyhedra, such as the capped trigonal cupola.

Spectroscopic Studies and Crystal Structures of Double Thorium(IV) Oxalates with Sodium Ions

“…Both 1 and 2 have tenfold coordination environments for Th atoms. Note that a CN of 10 is not very common for transition metals but is often observed in f‐element compounds 35. However, the majority of these structures belong to lanthanide compounds.…”

Curium(III) Borate Shows Coordination Environments of Both Plutonium(III) and Americium(III) Borates

“…The same coordination environment can only be found in Ce-[B 5 5 ] (Ln = LaNd). [16] The geometry of this coordination environment is best described as a capped triangular cupola [17] and can also be found in most of the Pu III centers in Pu III borates with capping halide ions. [12,13] Therefore, Cm III displays a bonding intermediate between that of Pu III and Am III not only with regard to the coordination numbers, but also with regard to the bonding interactions to the halide moieties.…”

Bonding Changes in Plutonium(III) and Americium(III) Borates

“…This environment forces the cations to have geometries that are not typically found for actinides in the trivalent oxidation state. Pu[B 4 O 6 (OH) 2 Cl] and Pu 2 [B 13 O 19 (OH) 5 Cl 2 (H 2 O) 3 ] both contain ten‐coordinate Pu III in a geometry that is best described as a capped triangular cupola 21. The capping group is a chloride anion, and the triangular base is created by either water molecules and borate anions in Pu 2 [B 13 O 19 (OH) 5 Cl 2 (H 2 O) 3 ], or borate and an additional chloride anion in Pu[B 4 O 6 (OH) 2 Cl].…”