3d transition elements

Paradoxical violations of Koopman s theorem with special reference to the 3d transition elements and the lanthanides. R. Ferreira, Struct. Bonding (Berlin), 1976, 31, 1-22 (73). 

Felsche J (1973) The Crystal Chemistry of the Rare-Earth Silicates. 13 99-197 Ferreira R (1976) Paradoxial Violations of Koopmans Theorem, with Special Reference to the 3d Transition Elements and the Lanthanides. 31 1-21 Fichtinger-Schepman AMJ, see Reedijk J (1987) 67 53-89... 

Ferreira, R. Paradoxical Violations of Koopmans Theorem, with Special Reference to the 3d Transition Elements and the Lanthanides. Vol. 31, pp. 1-21. 

Table 1.18 Crystal field stabilization energies for 3d transition elements according to McClure (1957) (1) and Dunitz and Orgel (1957) (2). ...

The Jahn-Teller principle finds applications both in the framework of crystal field theory and in the evaluation of energy levels through the LCAO-MO approach. In both cases, practical apphcations are restricted to 3d transition elements. 

The presence of magnetism amongst the 3d transition elements causes magnanese, iron, and cobalt not to obey the structural trend that is observed across the nonmagnetic 4d and 5d series. Manganese takes the a-Mn... 

Similar aspects arise for VO, except that vanadium belongs to the 3d transition element group. The electronic structure of VO is, however, similar to that of NbO and a large isotropic 53V hyperfine interaction arises from a 4s spin density of around 30%. 

One of the most valuable types of information available from the periodic table is the electron configuration of any representative element. If you understand the organization of the table, you do not need to memorize electron configurations for the elements. Although the predicted electron configurations for transition metals are sometimes incorrect, this is not a serious problem. You should, however, memorize the configuration of two exceptions, chromium and copper, since these 3d transition elements are found in many important compounds. 

In the present paper, we calculated the x-ray emission rates in molecnles with the DV-Xa method. We examine several factors affecting on the x-ray emission rates, estimate the chemical effect on the Kp/Ka ratios for 3d transition elements, and discuss the effect of the excitation modes on the KP/Ka ratios. 

TS, and RX methods for x-ray transition probabilities was made and it is demonstrated that relative intensity ratios and shapes of x-ray emission spectra are not so sensitive to the method used. The contributions of the interatomic transitions was estimated for CO and compounds of 3d transition metals. For C K-x-iay emission rates in CO the multi-center effect is found to be important, but in the case of the Kfij Ka ratios for the 3d transition elements the interatomic transitions are almost negligible. 

Qualitative information about the rate of ligand substitution in octahedral complexes is summarized in Table 18.1. Quantitative data are obtained by application of ligand field theory. The rate constants may vary by many orders of magnitude. Thus, for the exchange of water molecules in the first coordination sphere of 3d transition elements the following values have been measured Cr (d" ) 7 10 s Cr (d ) 5-10- s-i Mn2+(d5) 3-lO s- Fe2+(d ) 3-10 - Co + d ) 1 lOS Ni2+(d ) 3 104s-i. 

Ottoneho G., Piccardo G. B., and Ernst W. G. (1979) Petrogenesis of some Ligurian peridotites 2. Rare earth element chemistry. Geochim. Cosmochim. Acta 43,1273-1284. Ottonello G., Ernst W. G., and Joron J. L. (1984a) Rare earth and 3d transition elements geochemistry of peridotitic rocks ... 

However, Hansen et al. (5) measured -x-ray intensity ratios following A -capture decay of radioactive nuclei and pointed out that there is considerable difference between K/3 IKa ratios by electron-capture decay and those by x-ray or electron bombardment. Later, Paic and Pecar (6) found that the K/3 IKa x-ray intensity ratios for 3d transition elements depend on the mode of excitation. The K0/Ka ratios by electron-capture decay (EC) are smaller by almost ten per cent for Ti, V, Cr, and Fe than those by photoionization (PI). However, no appreciable difference was observed for Cu and Zn. A similar experiment was performed for Mn by Arndt et al. (7). They pointed out that the reason for this difference is due to the 3d excess electron in EC and the strong shakeoff process accompanying PI. Tamaki et al. (8) measured the K/3/Ka ratios for various chemical compounds of V, Cr, and Mn excited by PI and EC. 

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