RESUMO
Optical absorption and EPR studies of the mineral tenorite, a cupric oxide which originated from Mexico and contains 54.40 wt% of CuO. EPR spectral results indicate two Cu(II) closely interacting ions to give a d(2) type structure. The calculated spin Hamiltonian at room temperature and liquid nitrogen temperature is g=2.160 and D=125 G. The intensity of resonance line is not the same in low and high field regions. The optical absorption spectrum is due to Cu(II) in which three sets of energies indicating Cu(II) in two independent tetragonal C(4v) symmetry, in addition to d(2) structure of octahedral coordination. The octahedral and tetragonal field parameters are compared with those reported for several other copper containing minerals.
Assuntos
Cobre/química , Espectroscopia de Ressonância de Spin Eletrônica/métodos , Minerais/química , Óptica e Fotônica/métodos , Oligoelementos/química , Absorção , Temperatura , TermodinâmicaRESUMO
A sample of prehnite from Rayalaseema zone of Andhra Pradesh, India containing about 2.565 wt.% Fe(2)O(3) is used in the present work. The mineral has been characterized by EPMA, optical absorption, EPR, NIR and Mössbauer techniques. Mössbauer studies confirm the presence of iron as an impurity in two sites. An EPR study on powder sample confirm the presence of Fe(III) impurity in the mineral. Optical absorption spectrum also indicates that Fe(III) impurity is present in two sites with octahedral structure. NIR results are due to water fundamentals.
