Electronic structure of metal tetrahydroborates: quasi-relativistic X. cap alpha. -SW study of M(BH/sub 4/)/sub 4/ (M = Zr, Hf, Th, U)
Quasi-relativistic SCF-X..cap alpha.. scattered-wave calculations are presented for the series of metal tetrakis(tetrahydroborates) M(BH/sub 4/)/sub 4/ (M = Zr, Hf, Th, U). The bonding in the transition-metal compounds is that of tetrahedral d/sup 0/ complexes with strong covalent contributions from ..pi.. bonding ligand group orbitals. In the actinide complexes, 5f orbitals of the central atom are found to be important to covalent ligand-metal bonding but less than in the corresponding di-..pi..-(8)annulene compounds. The ligand field manifold of U(BH/sub 4/)/sub 4/ and the corresponding spin-orbit constant agree well with experimental data. Photoelectron spectra are reproduced satisfactorily with the exception of a uniform shift. An explanation is presented why the first ligand-derived band in the spectra of the actinide complexes is narrower than that in the transition-metal compounds. The difference between the zirconium and hafnium complexes in the splitting of the second band is found to be a relativistic effect due to a more effective covalent mixing of the Hf 6s orbital. 37 references, 5 figures, 6 tables.
- Research Organization:
- Technische Universitaet Muenchen, Garching, West Germany
- OSTI ID:
- 6909138
- Journal Information:
- Inorg. Chem.; (United States), Journal Name: Inorg. Chem.; (United States) Vol. 25:16; ISSN INOCA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
400201 -- Chemical & Physicochemical Properties
400702* -- Radiochemistry & Nuclear Chemistry-- Properties of Radioactive Materials
ACTINIDE COMPOUNDS
BORATES
BORON COMPOUNDS
CHEMICAL BONDS
DATA
ELECTRONIC STRUCTURE
EXPERIMENTAL DATA
HAFNIUM COMPOUNDS
INFORMATION
NUMERICAL DATA
OXYGEN COMPOUNDS
REFRACTORY METAL COMPOUNDS
THORIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
URANIUM COMPOUNDS
ZIRCONIUM COMPOUNDS