Details

Autor(en) / Beteiligte

• Lakshmi Reddy, S.
• Siva Reddy, G.
• Wain, D.L.
• Martens, W.N.
• Jagannatha Reddy, B.
• Frost, R.L.

Titel

Electron paramagnetic resonance, optical absorption and IR spectroscopic studies of the sulphate mineral apjohnite

Ist Teil von

• Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy, 2006-12, Vol.65 (5), p.1227-1233

Ort / Verlag

England: Elsevier B.V

Erscheinungsjahr

2006

Quelle

MEDLINE

Beschreibungen/Notizen

• Apjohnite, a naturally occurring Mn-bearing pseudo-alum from Terlano, Bolzano, Italy, has been characterized by EPR, optical, IR and Raman spectroscopy. The optical spectrum exhibits a number of electronic bands around 400 nm due to Mn(II) ion in apjohnite. From EPR studies, the parameters derived, g = 2.0 and A = 8.82 mT, confirm MnO(H 2O) 5 distorted octahedra. The presence of iron impurity in the mineral is reflected by a broad band centered around 8400 cm −1 in the NIR spectrum. A complex band profile appears strongly both in IR and Raman spectra with four component bands around 1100 cm −1 due to the reduction of symmetry for sulphate ion in the mineral. A strong pair of IR bands at 1681 and 1619 cm −1 with variable intensity is a proof for the presence of water in two states in the structure of apjohnite.