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Effects of temperature on the crystal structure of epidote: a neutron single-crystal diffraction study at 293 and 1,070 K

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Abstract

The effects of temperature on the crystal structure of a natural epidote [Ca1.925 Fe0.745Al2.265Ti0.004Si3.037O12(OH), a = 8.890(6), b = 5.630(4), c = 10.150(6) Å and β = 115.36(5)°, Sp. Gr. P21 /m] have been investigated by means of neutron single-crystal diffraction at 293 and 1,070 K. At room conditions, the structural refinement confirms the presence of Fe3+ at the M3 site [%Fe(M3) = 73.1(8)%] and all attempts to refine the amount of Fe at the M(1) site were unsuccessful. Only one independent proton site was located. Two possible hydrogen bonds, with O(2) and O(4) as acceptors [i.e. O(10)–H(1)···O(2) and O(10)–H(1)···O(4)], occur. However, the topological configuration of the bonds suggests that the O(10)–H(1)···O(4) is energetically more favourable, as H(1)···O(4) = 1.9731(28) Å, O(10)···O(4) = 2.9318(22) Å and O(10)–H(1)···O4 = 166.7(2)°, whereas H(1)···O(2) = 2.5921(23) Å, O(10)···O(2) = 2.8221(17) Å and O(10)–H(1)···O2 = 93.3(1)°. The O(10)–H(1) bond distance corrected for “riding motion” is 0.9943 Å. The diffraction data at 1,070 K show that epidote is stable within the T-range investigated, and that its crystallinity is maintained. A positive thermal expansion is observed along all the three crystallographic axes. At 1,070 K the structural refinement again shows that Fe3+ share the M(3) site along with Al3+ [%Fe(M3)1,070K = 74(2)%]. The refined amount of Fe3+ at the M(1) is not significant [%Fe(M1)1,070K = 1(2)%]. The tetrahedral and octahedral bond distances and angles show a slight distortion of the polyhedra at high-T, but a significant increase of the bond distances compared to those at room temperature is observed, especially for bond distances corrected for “rigid body motions”. The high-T conditions also affect the inter-polyhedral configurations: the bridging angle Si(2)–O(9)–Si(1) of the Si2O7 group increases significantly with T. The high-T structure refinement shows that no dehydration effect occurs at least within the T-range investigated. The configuration of the H-bonding is basically maintained with temperature. However, the hydrogen bond strength changes at 1,070 K, as the O(10)···O(4) and H(1)···O(4) distances are slightly longer than those at 293 K. The anisotropic displacement parameters of the proton site are significantly larger than those at room condition. Reasons for the thermal stability of epidote up to 1,070 K observed in this study, the absence of dehydration and/or non-convergent ordering of Al and Fe3+ between different octahedral sites and/or convergent ordering on M(3) are discussed.

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References

  • Bedognè F, Montrasio A, Sciesa E (1993) Valmalenco—I minerali della provincia di Sondrio. Bettini, Sondrio (Italy), 275 p

  • Bird DK, Helgeson HC (1980) Chemical interaction of aqueous solutions with epidote-feldspar mineral assemblages in geologic systems, I: thermodynamic analysis of phase relations in the system CaO-FeO-Fe2O3-Al2O3-SiO2–H2O-CO2. Am J Sci 280:907–941

    Google Scholar 

  • Bird DK, Cho M, Janik CJ, Liou JG, Caruso LJ (1988) Compositional, order–disorder, and stable isotopic characteristics of Al–Fe epidote, state 2–14 drill hole, Salton Sea geothermal system. J Geophys Res 93(B11):13135–13144

    Article  Google Scholar 

  • Bonazzi P, Menchetti S (1995) Monoclinic members of the epidote group: effect of the Al↔Fe3+↔Fe2+ substitution and of the entry of REE3+. Mineral Petrol 53:133–153

    Article  Google Scholar 

  • Bonazzi P, Menchetti S (2004) Manganese in monoclinic members of the epidote group: piemontite and related minerals. In: Franz G, Liebscher A (eds) Epidotes. Reviews in Mineralogy and Geochemistry, Mineralogical Society of America and Geochemical Society, Washington 56:495–552

  • Busing WR, Levy HA (1964) The effect of thermal motion on the estimation of bond lengths from diffraction measurements. Acta Crystallogr 17:142–146

    Article  Google Scholar 

  • Carbonin S, Molin G (1980) Crystal-chemical considerations of eight metamorphic epidotes. N Jb Mineral Abh 139:205–215

    Google Scholar 

  • Catti M, Ferraris G, Ivaldi G (1988) Thermal behaviour of the crystal structure of strontian piemontite. Am Mineral 73:1370–1376

    Google Scholar 

  • Comodi P, Zanazzi PF (1997) The pressure behaviour of clinozoisite and zoisite. An X-ray diffraction study. Am Mineral 82:61–68

    Google Scholar 

  • Dollase WA (1968) Refinement and comparison of the structures of zoisite and clinozoisite. Am Mineral 53:1882–1898

    Google Scholar 

  • Dollase WA (1969) Crystal structure and cation ordering of piemontite. Am Mineral 54:710–717

    Google Scholar 

  • Dollase WA (1971) Refinement of the crystal structure of epidote, allanite and hancockite. Am Mineral 56:447–464

    Google Scholar 

  • Dollase WA (1973) Mössbauer spectra and iron distribution in the epidote-group minerals. Z Kristallogr 138:41–63

    Article  Google Scholar 

  • Downs RT (2000) Analysis of harmonic displacement factors. In: Hazen RM, Downs RT (eds) High-temperature and high-pressure crystal chemistry. Reviews in Mineralogy and Geochemistry, Mineralogical Society of America and Geochemical Society, Washington 41:61–117

  • Downs RT, Gibbs GV, Bartelmehs KL, Boisen MB Jr (1992) Variations of bond lengths and volumes of silicate tetrahedra with temperature. Am Mineral 77:751–757

    Google Scholar 

  • Farrugia LJ (1999) WinGX suite for small-molecule single-crystal crystallography. J Appl Crystallogr 32:837–838

    Article  Google Scholar 

  • Fehr KT, Heuss-Assbichler S (1997) Intracrystalline equilibria and immiscibility gap along the join clinozoisite-epidote: An experimental and 57Fe Mössbauer study. N Jb Mineral Abh 172:43–67

    Google Scholar 

  • Franz G, Liebscher A (2004) Physical and chemical properties of epidote minerals—an introduction. In: Franz G, Liebscher A (eds) Epidotes. Reviews in Mineralogy and Geochemistry, Mineralogical Society of America and Geochemical Society, Washington 56:1–81

  • Gabe EJ, Portheine FC, Whitlow SH (1973) A reinvestigation of the epidote structure: confirmation of the iron location. Am Mineral 58:218–223

    Google Scholar 

  • Giuli G, Bonazzi P, Menchetti S (1999) Al–Fe disorder in synthetic epidotes: a single-crystal X-ray diffraction study. Am Mineral 84:933–936

    Google Scholar 

  • Gottschalk M (2004) Thermodynamic properties of zoisite, clinozoisite and epidote. In: Franz G, Liebscher A (eds) Epidotes. Reviews in Mineralogy and Geochemistry, Mineralogical Society of America and Geochemical Society, Washington 56:83–124

  • Hanisch K, Zemann J (1966) Messung des Ultrarot-Pleochroismus von Mineralen. IV. Der Pleochroismus der OH-Streckfrequenz in Epidot. N Jb Mineral Mon 1966:19–23

  • Holdaway MJ (1972) Thermal stability of Al–Fe epidotes as a function of fO2 and Fe content. Contrib Min Petrol 37:307–340

    Article  Google Scholar 

  • Ito T, Morimoto N, Sadanga R (1954) On the structure of epidote. Acta Crystallogr 7:53–59

    Article  Google Scholar 

  • Klemd R (2004) Fluid inclusions in epidote minerals and fluid development in epidote-bearing rocks. In: Franz G, Liebscher A (eds) Epidotes. Reviews in Mineralogy and Geochemistry, Mineralogical Society of America and Geochemical Society, Washington 56:197s–234s

  • Kvick Å, Pluth JJ, Richardson JW Jr, Smith JV (1988) The ferric ion distribution and hydrogen bonding in epidote: a neutron diffraction study at 15 K. Acta Crystallogr B44:351–355

    Google Scholar 

  • Langer K, Raith M (1974) Infrared spectra of Al–Fe(III)-epidotes and zoisites Ca2(Al1-p Fe 3+ p )Al2O(OH)[Si2O7][SiO4]. Am Mineral 59:1249–1258

    Google Scholar 

  • Larson AC (1970) Crystallographic computing. Ahmed FR, Hall SR, Huber CP (eds) Copenhagen, Denmark, Munksgaard, pp 291–294

  • Liebscher A (2004) Spectroscopy of epidote minerals. In: Franz G, Liebscher A (eds) Epidotes. Reviews in Mineralogy and Geochemistry, Mineralogical Society of America and Geochemical Society, Washington 56:125–170

  • Liebscher A, Gottschalk M, Franz G (2002) The substitution Fe3+–Al and the isosymmetric displacive phase transition in synthetic zoisite: a powder X-ray and infrared spectroscopy study. Am Mineral 87:909–921

    Google Scholar 

  • Liou JG (1973) Synthesis and stability relations of epidote, Ca2Al2FeSi3O12(OH). J Petrol 14:381–413

    Google Scholar 

  • Nozik YK, Kanepit VN, Fykin LY, Makarov YS (1978) A neutron diffraction study of the structure of epidote. Geochem Int 15:66–69

    Google Scholar 

  • Poli S, Schmidt MW (2004) Experimental subsolidus studies on epidote minerals. In: Franz G, Liebscher A (eds) Epidotes. Reviews in Mineralogy and Geochemistry, Mineralogical Society of America and Geochemical Society, Washington 56:171–195

  • Robinson K, Gibbs GV, Ribbe PH (1971) Quadratic elongation: a quantitative measure of distortion in coordination polyhedra. Science 172:567–570

    Article  Google Scholar 

  • Schmidt MW, Poli S (2004) Magmatic epidotes. In: Franz G, Liebscher A (eds) Epidotes. Reviews in Mineralogy and Geochemistry, Mineralogical Society of America and Geochemical Society, Washington 56:399–430

  • Sears VF (1986) Neutron scattering lengths and cross-sections. In: Sköld K, Price DL (eds) Neutron scattering, methods of experimental physics, vol 23A. Academic Press, New York, pp 521–550

    Chapter  Google Scholar 

  • Sheldrick GM (1997) SHELX-97. Programs for crystal structure determination and refinement. University of Göttingen, Germany

    Google Scholar 

  • Smith JV, Pluth JJ, Richardson JW Jr, Kvick Å (1988) Neutron diffraction study of zoisite at 15 K and X-ray study at room temperature. Z Kristallogr 179:305–321

    Google Scholar 

  • Stergiou AC, Rentzeperis PJ, Sklavounos S (1987) Refinement of the crystal structure of a medium iron epidote. Z Kristallogr 178:297–305

    Google Scholar 

Download references

Acknowledgments

The authors thank the Forschungsneutronenquelle Heinz Maier-Leibnitz (FRM-II), München, Germany, for the allocation of neutron beam time. This work was also funded by the Italian Ministry of University and Research, MIUR-Project: 2006040119_004. The editor Milan Rieder, Roman Skala and an anonymous reviewer are thanked.

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Authors and Affiliations

  1. Dipartimento di Scienze della Terra, Università degli Studi di Milano, Via Botticelli, 23, 20133, Milan, Italy

    G. Diego Gatta

  2. CNR-Istituto per la Dinamica dei Processi Ambientali, Milan, Italy

    G. Diego Gatta

  3. Forschungsneutronenquelle Heinz Maier-Leibnitz (FRM-II), Munich, Germany

    Martin Meven

  4. School of GeoSciences, The University of Edinburgh, Edinburgh, UK

    Geoffrey Bromiley

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  1. G. Diego Gatta
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  2. Martin Meven
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Correspondence to G. Diego Gatta.

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Gatta, G.D., Meven, M. & Bromiley, G. Effects of temperature on the crystal structure of epidote: a neutron single-crystal diffraction study at 293 and 1,070 K. Phys Chem Minerals 37, 475–485 (2010). https://doi.org/10.1007/s00269-009-0348-5

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