ISSN:
1432-2021
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Geosciences
,
Physics
Notes:
Abstract Polarized optical absorption spectra of Mn(IV) in octahedral crystal fields of Mn(SeO3)2 have been studied by means of microscope-spectrometry in the range 40000-4000 cm−1 and at temperatures between 113 K and 293 K. Intense charge-transfer absorptions (linear absorption coefficient α ≫ 30000 cm−1) completely mask the d-d transitions in the UV and VIS region above ≈23000 cm−1. The optical electronegativity χ opt of Mn(IV) in Mn(SeO3)2 is estimated to be 2.7. In accordance with the d 3 configuration of tetravalent manganese three d-d bands observed at ambient temperatures at 13250, 14137 (α≈50 cm−1) and ≈18500 cm−1 (α≈500–800 cm−1) are assigned to the spin forbidden 4 A 2g →2 E g and 4 A 2g →2 T 1g transitions as well as to the first spin allowed 4 A 2g →4 T 2g transition, respectively. These assignments allow the calculation of the following ligand field parameters: Dq ≈ 1850 cm−1, B 55 = 869 cm−1 (β 55 = 0.82), and C = 2346 cm−1 (293 K).
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00202093
