title: EPR and optical absorption spectral studies on sphalerite mineral.
abstract: The mineral sphalerite (Zn,Fe)S has been characterized by a combination of X-ray diffraction, EPR and NIR spectroscopy. The optical absorption spectrum of mineral sphalerite is due to an iron impurity only, which is in a distorted octahedral environment. The g=2.2 is attributed to iron and g and A value observed in the spectrum 1.999 and 6.0 mT are assigned to Mn(II) impurity in the mineral. These results indicate that iron and Mn(II) impurity have entered the lattice by substitution. The EPR results confirm the presence of manganese in a distorted octahedral environment. It is evident from the chemical analysis that iron is present in higher concentrations. NIR results are due to the presence of water and sulphide fundamentals which also support the formula of the mineral. No sulphate in the sphalerite mineral was observed.
authors.affiliation: Dept. of Chemistry, Tirupati 517 502, India.
authors.forename: K
authors.initials: K
authors.lastname: Seshamaheswaramma
authors.forename: G Udayabhaskara
authors.initials: GU
authors.lastname: Reddy
authors.forename: A Varada
authors.initials: AV
authors.lastname: Reddy
authors.forename: S
authors.initials: S
authors.lastname: Lakshmi Reddy
authors.forename: R L
authors.initials: RL
authors.lastname: Frost
authors.forename: Tamio
authors.initials: T
authors.lastname: Endo
mesh_terms: D000042:Absorption; D004578:Electron Spin Resonance Spectroscopy; D007501:Iron / Q000737:chemistry; D008345:Manganese / Q000737:chemistry; D008903:Minerals / Q000737:chemistry; D009904:Optical Rotation; D019265:Spectroscopy, Near-Infrared; D013440:Sulfides / Q000737:chemistry*; D014961:X-Ray Diffraction; D017967:Zinc Compounds / Q000737:chemistry*
chemical_list: D008903:Minerals; D013440:Sulfides; D017967:Zinc Compounds; D008345:Manganese; D007501:Iron; C031238:zinc sulfide