Octahedral electronic spectra

Eg term. A magnetic moment of around 5.5 BM (i.e. 4.90 BM- -orbital contribution) is expected for pure octahedral symmetry but, in practice, distortions produce values in the range 5.2-5.4BM. Similarly, in the electronic spectrum, the expected single band due to the Eg t ge g) T2g t ge ) transition is broadened... 

Acetylpyridine thiosemicarbazone forms [Co(8)2Cl2], which is isolated from hot ethanol [178], Based on infrared spectra the pyridyl nitrogen is coordinated and bonding is NS with two chlorines bringing the coordination number to six. The complex is a non-electrolyte in DMF, has a magnetic moment of 4.13 B.M., and the electronic spectrum has bands at about 8160 and 17 860 cm consistent with octahedral stereochemistry. 

Solutions of CrCl2-2CH3CN and the wet solid are extremely sensitive to oxygen. When dried, however, the complex remains unchanged in air for several minutes before oxidation becomes apparent. It is virtually insoluble in acetonitrile but quite soluble in ethanol. The room-temperature magnetic moment (4.8 B.M.) and electronic spectrum are consistent with a high-spin distorted octahedral Cr2+ ion.15... 

The electronic spectrum (36) of the pol5uner is dominated by a very broad ultraviolet band, with shoulders at 280 and 470 m/t, which tails into the visible region and is responsible for the deep brown color of the polymer. Very weak crystal field excitations are found at 640 and 880 m. From the latter transition one can estimate that for high-spin Fe +, Dq = 1100 cm i. This value is typical of Fe3+ in octahedral coordination with oxygen ligands, but the X-ray evidence (see below) indicates that the coordination is tetrahedral, so that Dq seems anomalously high. However, the coordination symmetry is actually lower than tetrahedral, since both hydroxide and oxide ligands are involved. 

For a weak CF the ground CFT is 5Eg and the first excited CFT lies at A0 = 10Dq. The electronic spectrum for the octahedral complex also contains a transition A to the 3 Tig term arising from the free-atom 3H term (this is spin forbidden and consequently of a weak intensity, Table 73 and Fig. 123). 

The enzyme contains six identical subunits (M = 96600) arranged in the form of an octahedron. Each subunit contains two tightly bound nickel ions (% nickel = 0.12). After the electronic spectrum of the enzyme has been corrected for light scattering the d-d bands associated with nickel(II) at 407, 747 and 1060 nm are consistent with nickel in an octahedral environment. In the presence of acetohydroxamic acid the... 

An allegedly square planar complex OsLj (L = dithiobenzil) was claimed in 1964706 but was later that year reformulated as the octahedral tris complex OsL3.707 No clear preparative details were given of this red complex, but the electronic spectrum and electrical conductance were later reported.708... 

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