Abstracts 1997

Abstract of Publication No. 282

Thomas C. Brunold and Hans U. Güdel
Ruthenium(VI) Doped into Single Crystals with the BaSO4 and b-K2SO4 Structures:
Optical Absorption Spectra of RuO42-

Inorg. Chem. 36, 2084-2091 (1997)      Full Text (PDF)      DOI-Link     

Abstract: By establishing suitable high-temperature preparation conditions we were able to grow the first RuO42--doped crystals of K2CrO4, K2SeO4, Cs2MoO4, BaSO4, BaCrO4, and BaSeO4. Their polarized absorption spectra at low temperatures are reported and discussed. These are very different from the ruthenate(VI) spectra in the literature, and the lack of resemblance between calculated and measured spectra of ruthenate(VI)-assumed to be RuO42- in the past-is easily understood. The 3A2 1A1 spin-flip transition of RuO42- peaks at 7100 cm1. Stronger bands due to 3A2 3T2 and 3T1 are observed in the vis around 13 500 and 16 500 cm1, respectively, giving rise to the green-blue color of most samples. In the BaSO4 host the 1A1 absorption line is split into three differently polarized components exhibiting a strong temperature dependence. This can be analyzed in terms of a Boltzmann population with three levels at 0, 13, and 18 cm1, corresponding to the three spinor components of the 3A2 ground state. In order to better understand the major changes which occur on going from the 3d2 to the 4d2 electron configuration the spectroscopic data of RuO42- are compared with those of CrO44-, MnO43-, and FeO42-.

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