ChemInform Abstract: Formation, Structure and Luminescent Properties of Metal-Metal Bonded Compounds of the Late Transition Metal and Post Transition Metal Ions

ChemInform ◽  
2010 ◽  
Vol 23 (5) ◽  
pp. no-no
Author(s):  
A. L. BALCH
Keyword(s):  
Transition Metal ◽  
Metal Ions ◽  
Luminescent Properties ◽  
Transition Metal Ions ◽  
Late Transition Metal ◽  
Metal Metal ◽  
Late Transition

Calculation of crystal field splittings in distorted coordination polyhedra: spectra and thermodynamic properties of minerals

1972 ◽  
Vol 38 (300) ◽  
pp. 909-917 ◽  
Author(s):  
Bernard J. Wood ◽  
R. G. J. Strens
Keyword(s):  
Charge Transfer ◽  
Transition Metal ◽  
Metal Ions ◽  
Crystal Field ◽  
Transition Metal Ions ◽  
Orbital Energy ◽  
Absorption Bands ◽  
Simple Method ◽  
Coordination Polyhedra ◽  
Metal Metal

SummaryA simple method has been developed for calculating the d-orbital energy levels of transition-metal ions in coordination polyhedra with both orthogonal and non-orthogonal distortions, using equations based on those derived by Ballhausen (1954). The input data are atomic coordinates, a standard value of the crystal field splitting parameter Δ at known metal-ligand distance, and the ratio of radial integrals B2/B4, which is approximately constant for a given ion. The method can be applied to polyhedra containing different ligands.Application of the equations to the Mn3+ (M3) site in piemontite and the Fe2+ (M2) site in orthopyroxene gives calculated transition energies in good agreement with the observed band energies.The calculations permit definite assignment of the great majority of d-d absorption bands even in multi-site phases, and enable discrimination of crystal-field and charge-transfer bands in mineral spectra. They also throw light on the fine structures of both oxygen → metal and metal → metal charge-transfer bands, and allow the calculation of crystal-field stabilization enthalpy and electronic entropy. The latter is a previously neglected energy term that contributes significantly to the energetics of reactions within and between phases containing transition-metal ions.

HREM Study of electron-induced surface radiation damage in ReO3

1991 ◽  
Vol 49 ◽  
pp. 636-637
Author(s):  
R. Ai ◽  
H.-J. Fan ◽  
L. D. Marks
Keyword(s):  
Transition Metal ◽  
Metal Ions ◽  
Metal Oxides ◽  
Electron Irradiation ◽  
Transition Metal Oxides ◽  
Carbon Film ◽  
Transition Metal Ions ◽  
Surface Radiation ◽  
Valence Transition ◽  
Electron Microscopes

It has been known for a long time that electron irradiation induces damage in maximal valence transition metal oxides such as TiO2, V2O5, and WO3, of which transition metal ions have an empty d-shell. This type of damage is excited by electronic transition and can be explained by the Knoteck-Feibelman mechanism (K-F mechanism). Although the K-F mechanism predicts that no damage should occur in transition metal oxides of which the transition metal ions have a partially filled d-shell, namely submaximal valence transition metal oxides, our recent study on ReO3 shows that submaximal valence transition metal oxides undergo damage during electron irradiation.ReO3 has a nearly cubic structure and contains a single unit in its cell: a = 3.73 Å, and α = 89°34'. TEM specimens were prepared by depositing dry powders onto a holey carbon film supported on a copper grid. Specimens were examined in Hitachi H-9000 and UHV H-9000 electron microscopes both operated at 300 keV accelerating voltage. The electron beam flux was maintained at about 10 A/cm2 during the observation.

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