Abstract
The electronic absorption spectra of three biotites with largely differing Fe2+/Fe3+ ratios were studied before and after thermal dehydration and oxidation of divalent iron. Three absorption bands near 17,100, 20,500 and 24,100 cm−1 and an absorption edge at slightly higher energies are assigned to trivalent iron present in clusters of strongly interacting ions. The presence of additional broad absorption bands due to intervalence transfer between Fe2+ and Fe3+ or Ti4+ in this region cannot be excluded for biotites with high Fe2+ concentrations. Three bands at lower energies show a satisfactory correlation with concentration of divalent iron and decrease in the same proportions with oxidation. We therefore assign them to split components of the spin-allowed ligand field transition of Fe2+ at the M 1 and M 2 sites. This contradicts the assignment of one of these bands to an intervalence charge transfer between Fe2+ and Fe3+ by previous authors. It is shown that there is no indisputable evidence against our assignment.
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References
Annersten, H.: Mössbauer studies of natural biotites. Am. Mineral. 59, 143–151 (1974)
Deer, W.A., Howie, R.A., Zussman, J.: Rock Forming Silicates, 3. Sheet Silicates. London: Longmans 1962
Dodge, F.C.W., Smith, V.C., Mays, R.E.: Biotites from granitic rocks of the Central Sierra Nevada batholith, California. Petrol. 10, 250–271 (1969)
Donnay, G., Morimoto, N., Takeda, H., Donnay, J.D.H.: Trioctahedral one-layer micas. I. Crystal structure of synthetic iron mica. Acta Cryst. 17, 1369–1373 (1964)
Eppels, K., Lehmann, G.: Intensities of ligand field bands for hexa-co-ordinated copper (II) and nickel (II) in pure and doped single crystals. J. Chem. Res. (S) pp. 284–285, 1977, J. Chem. Res. (M) 3169–3197 1977
Faye, G.H.: Optical absorption spectra of iron in six-coordinate sites in chlorite, biotite, phlogopite and vivianite. Some aspects of pleochroism in the sheet silicates. Can. Mineral. 9, 403–425 (1968)
Ferguson, J., Guggenheim, H.J., Tanabe, Y.: Simultaneous electronic excitation of exchange-coupled pairs of managanese and nickel ions. Phys. Rev. 161, 207–212 (1967)
Forrester, P.A., Schneider, E.E.: Paramagnetic resonance of manganese in single crystals of alkali halides. Proc. Phys. Soc. 69B, 833–837 (1956)
Foster, M.B.: Interpretation of the composition of trioctahedral micas. US Geol. Surv. Prof. Pap. 354B. (1960)
Franzini, M., Schiaffino, L.: On the crystal structure of biotites. Z. Krist. 119, 297–309 (1964)
Häggström, L., Wäppling, R., Annersten, H.: Mössbauer study of oxidized iron silicate minerals. Phys. Status Solidi 33, 741–748 (1969)
Hogg, C.S., Meads, R.E.: The Mössbauer spectra of several micas and related minerals. Mineral. Mag. 37, 606–614 (1970)
Hogg, C.S., Meads, R.E.: A Mössbauer study of thermal decomposition of biotites. Mineral. Mag. 40, 79–88 (1975)
Iri, T., Kuwabara, G.: Paramagnetic resonance of Mn2+ in CsBr. J. Phys. Soc. Japan 23, 536–539 (1967)
Krebs, J.J., Maisch, W.G.: Exchange effects in the optical absorption spectrum of Fe3+ in Al2O3. Phys. Rev. B 4, 757–769 (1971)
Kotlicki, A., Olsen, N.B., Olsen, J.S.: Mössbauer and X-ray study of proton radiation effects in biotite. Radiation Effects 28, 1–4 (1976)
Larsen, Jr., E.S., Gonyer, F.A., Irving, J.: Petrologic results of a study of the minerals from the tertiary volcanic rocks of the San Juan Region, Colorado. Am. Mineral. 22, 898–905 (1937)
Lehmann, G.: Ligand field and charge transfer spectra of Fe (III)-O complexes. Z. Phys. Chem. (Frankfurt) 72, 279–297 (1970)
Lehmann, G., Gudat, A.E.: Coupling between ligand field and charge transfer states in tetrahedral CoX 2−4 complexes. Z. Phys. Chem. (Frankfurt) 93, 327–336 (1974)
Lohr, Jr., L.L., McClure, D.S.: Optical spectra of divalent manganese salts. II. The effect of interionic coupling on absorption strength. J. Chem. Phys. 49, 3516–3521 (1968)
Low, W.: Paramagnetic resonance spectrum of manganese in single crystals of alkali halides grown from solutions. Proc. Phys. Soc. 69B, 837–838 (1956)
McClure, D.S.: Optical spectra of exchange coupled Mn2+ ion pairs in ZnS: MnS. J. Chem. Phys. 39, 2850–2855 (1963)
Oshima, V., Abe, H., Nagano, H., Nagusa, M.: Paramagnetic resonance of NaCl crystals containing additions of manganese impurity. J. Chem. Phys. 23, 1721–1722 (1955)
Rimsaite, J.: Studies of rock-forming micas. Geol. Surv. Canada Bull. 149 (1967)
Rimsaite, J.: Structural formulae of oxidized and hydroxyl-deficient micas and decomposition of the hydroxyl group. Contrib. Mineral. Petrol. 25, 225–240 (1970)
Robbins, D.W., Strens, R.G.J.: Charge transfer in ferromagnesian silicates: The polarized electronic spectra of trioctahedral micas. Mineral. Mag. 38, 551–563 (1972)
Rossman, G.R.: The optical spectroscopic comparison of the ferric iron tetrameric clusters in amarantite and leucophosphite. Am. Mineral. 61, 933–938 (1976)
Smith, G.: Low temperature optical studies of metal-metal charge-transfer transitions in various minerals. Can. Mineral. 15, 500–507 (1977)
Smith, G., Strens, R.G.J.: Intervalence-transfer absorption in some silicate, oxide and phosphate minerals. Phys. Chem. Mineral. Rocks (R.G.J. Strens, ed.), 583–612. New York: Wiley 1976
Stock, H.D., Lehmann, G.: Phenomena associated with diffusion of trivalent iron in amethyst quartz. J. Phys. Chem. Solids 38, 243–246 (1977)
Vedder, W.: Correlations between the infrared spectrum and chemical composition of biotite mica. Am. Mineral. 49, 736–768 (1964)
Vedder, W., Wilkins, R.W.T.: Dehydroxylation and rehydroxylation, oxidation and reduction of micas. Am. Mineral. 54, 482–509 (1969)
Wilkins, R.W.T.: The hydroxyl stretching region of the spectrum of biotite mica. Mineral. Mag. 36, 325–333 (1964)
Wilson, A.D.: Micro-determination of ferrous iron in silicate minerals by volumetric and colorimetric methods. The Analyst 85, 823–827 (1960)
Wulfing, C., Jones, R.B., Gray, H.B.: The structures of iron (III) in aqueous solution. J. Am. Chem. Soc. 89, 3712–3720 (1967)
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Kliem, W., Lehmann, G. A reassignment of the optical absorption bands in biotites. Phys Chem Minerals 4, 65–75 (1979). https://doi.org/10.1007/BF00308360
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DOI: https://doi.org/10.1007/BF00308360