Polarized electronic absorption spectra of colourless chalcocyanite, CuSO<sub>4</sub>, with a survey on crystal fields in Cu<sup>2+</sup> minerals
- Autor(en)
- Manfred Wildner, Gerald Giester, Monika Kersten, Klaus Langer
- Abstrakt
Polarized electronic absorption spectra of colorless chalcocyanite, CuSO4, have been measured using microscope-?spectrometric techniques. The spectra are characterized by a structured and clearly polarized band system in the near-?IR spectral range with components centered at 11,?720, 10,?545, 9,?100, and 7,?320 cm-?1, which have been assigned to crystal field d-?d transitions of Cu2+ cations in pseudo-?tetragonally elongated CuO6 polyhedra with point symmetry Ci (1[n.773]?)?. The polarization behavior is interpreted based on a D2(C2'') pseudo-?symmetry. Crystal field calcns. were performed for the actual triclinic point symmetry by applying the Superposition Model of crystal fields, as well as in terms of a 'classic' pseudo-?tetragonal crystal field approach yielding the parameters Dq(eq)? = 910, Dt = 395, and Ds = 1,?336 cm-?1, corresponding to a cubically averaged Dqcub = 679 cm-?1. A comparative survey on crystal fields in Cu2+ minerals shows that the low overall crystal field strength in chalcocyanite, combined with a comparatively weak pseudo-?tetragonal splitting of energy levels, is responsible for its unique colorless appearance among oxygen-?based Cu2+ minerals. The weak crystal field in CuSO4 can be related to the lower position of the SO42-? anion compared to, e.g. the H2O mol. in the spectrochem. series of ligands.
- Organisation(en)
- Institut für Mineralogie und Kristallographie
- Externe Organisation(en)
- Technische Universität Berlin
- Journal
- Physics and Chemistry of Minerals
- Band
- 41
- Seiten
- 669-680
- Anzahl der Seiten
- 12
- ISSN
- 0342-1791
- DOI
- https://doi.org/10.1007/s00269-014-0681-1
- Publikationsdatum
- 05-2014
- Peer-reviewed
- Ja
- ÖFOS 2012
- 105116 Mineralogie, 105113 Kristallographie, 1030 Physik, Astronomie
- Schlagwörter
- ASJC Scopus Sachgebiete
- Allgemeine Materialwissenschaften, Geochemistry and Petrology
- Link zum Portal
- https://ucrisportal.univie.ac.at/de/publications/cdb1fd96-2109-40d5-8994-6e79ddbbc719