Physics and Chemistry of Minerals

, Volume 41, Issue 7, pp 519–526 | Cite as

Chromium solubility in MgSiO3 ilmenite at high pressure

  • Luca Bindi
  • Ekaterina A. Sirotkina
  • Andrey V. Bobrov
  • Tetsuo Irifune
Original Paper


The crystal structure and chemical composition of crystals of (Mg1−x Cr x )(Si1−x Cr x )O3 ilmenite (with x = 0.015, 0.023 and 0.038) synthesized in the model system Mg3Cr2Si3O12–Mg4Si4O12 at 18–19 GPa and 1,600 °C have been investigated. Chromium was found as substitute for both Mg at the octahedral X site and Si at the octahedral Y site, according to the reaction Mg2+ + Si4+ = 2Cr3+. Such substitutions cause a shortening of the <X–O> and a lengthening of the <Y–O> distances with respect to the values typically observed for pure MgSiO3 ilmenite and eskolaite Cr2O3. Although no high Cr contents are considered in the pyrolite model, Cr-bearing ilmenite may be the host for chromium in the Earth’s transition zone. The successful synthesis of ilmenite with high Cr contents and its structural characterization are of key importance because the study of its thermodynamic constants combined with the data on phase relations in the lower-mantle systems can help in the understanding of the seismic velocity and density profiles of the transition zone and the constraining composition and mineralogy of pyrolite in this area of the Earth.


Ilmenite Chromium Earth’s transition zone Crystal structure Microprobe analysis Synthesis 



The manuscript took advantage from the revision of two anonymous reviewers. The research was supported by “progetto di Ateneo 2012, University of Firenze” to LB, by C.N.R., Istituto di Geoscienze e Georisorse sezione di Firenze, Italy, the Russian Foundation for Basic Research (Project Nos. 12-05-00426, 12-05-33044, and 14-05-31288) and by the Foundation of the President of the Russian Federation for Leading Scientific Schools (Project No. NSh-5877.2012.5) to ES and AB. ES thanks Geodynamics Research Center, Ehime University, Matsuyama, Japan, for support of her visit in 2013.


  1. Akaogi M, Tanaka A, Ito E (2002) Garnet–ilmenite–perovskite transitions in the system Mg4Si4O12–Mg3Al2Si3O12 at high pressures and high temperatures: phase equilibria, calorimetry and implications for mantle structure. Phys Earth Planet Inter 132:303–324CrossRefGoogle Scholar
  2. Albee AL, Ray L (1970) Correction factors for electron probe analysis of silicate, oxides, carbonates, phosphates, and sulfates. Anal Chem 48:1408–1414CrossRefGoogle Scholar
  3. Allègre JA, Poirier JP, Humler E, Hofmann AW (1995) The chemical composition of the Earth. Earth Plan Sci Lett 134:515–526CrossRefGoogle Scholar
  4. Bence AE, Albee AL (1968) Empirical correction factors for the electron microanalysis of silicate and oxides. J Geol 76:382–403CrossRefGoogle Scholar
  5. Bindi L, Sirotkina E, Bobrov AV, Irifune T (2014a) Chromium solubility in perovskite at high pressure: The structure of (Mg1−xCrx)(Si1−xCrx)O3 (with x = 0.07) synthesized at 23 GPa and 1600 °C. Am Miner. doi: 10.2138/am.2014.4784
  6. Bindi L, Sirotkina E, Bobrov AV, Irifune T (2014b) X-ray single-crystal structural characterization of MgCr2O4, a post-spinel phase synthesized at 23 GPa and 1600 °C. J Phys Chem Solids 75:638–641CrossRefGoogle Scholar
  7. Bykova E, Bobrov AV, Sirotkina EA, Bindi L, Ovsyannikov SV, Dubrovinsky LS, Litvin YuA (2013) X-ray single-crystal and Raman study of knorringite, Mg3(Cr1.58Mg0.21Si0.21)Si3O12, synthesized at 16 GPa and 1600 °C. Phys Chem Miner. doi: 10.1007/s00269-013-0644-y
  8. Dobson DP, Jacobsen SD (2004) The flux growth of magnesium silicate perovskite single crystals. Am Miner 89:807–811Google Scholar
  9. Horiuchi H, Hirano M, Ito E, Matsui Y (1982) MgSiO3 (ilmenite-type): single crystal X-ray diffraction study. Am Miner 67:788–793Google Scholar
  10. Ibers JA, Hamilton WC (eds) (1974) International tables for X-ray crystallography, vol IV. Kynock, Dordrecht, p 366Google Scholar
  11. Irifune T, Kurio A, Sakamoto S, Inoue T, Sumiya H, Funakoshi K (2004) Formation of pure polycrystalline diamond by direct conversion of graphite at high pressure and high temperature. Phys Earth Planet Inter 143–144:593–600CrossRefGoogle Scholar
  12. Ito E, Navrotsky A (1985) MgSiO3 ilmenite; Calorimetry, phase equilibria and decomposition at atmospheric pressure. Am Miner 70:1020–1026Google Scholar
  13. Ito E, Yamada H (1982) Stability relations of silicate spinels, ilmenites and perovskites. In: Akimoto S, Manghnani MH (eds) High pressure research in geophysics. Center of Academic Publications, Tokyo, pp 405–419CrossRefGoogle Scholar
  14. Karki B, Duan W, da Silva CRS, Wentzcovitch RM (2000) Ab initio structure of MgSiO3 ilmenite at high pressure. Am Miner 85:317–320Google Scholar
  15. Katsura T, Ito E (1989) The system Mg2SiO4–Fe2SiO4 at high pressure and temperatures: precise determination of stabilities of olivine, modified spinel, and spinel. J Geophys Res 94:15663–15670CrossRefGoogle Scholar
  16. Kubo A, Akaogi M (2000) Post-garnet transitions in the system Mg4Si4O12–Mg3Al2Si3O12 up to 28 GPa: phase relations of garnet, ilmenite and perovskite. Phys Earth Planet Inter 121:85–102CrossRefGoogle Scholar
  17. Matsui M, Akaogi M, Matsumoto T (1987) Computational model of the structural and elastic properties of the ilmenite and perovskite phase of MgSiO3. Phys Chem Miner 14:101–106CrossRefGoogle Scholar
  18. Miyajima N, El Goresy A, Dupas-Bruzek C, Seifert F, Rubie DC, Chen M, Xie X (2007) Ferric iron in Al-bearing akimotoite coexisting with iron–nickel metal in a shock-melt vein in an L-6 chondrite. Am Miner 92:1545–1549CrossRefGoogle Scholar
  19. Niu F, Kawakatsu H (1996) Complex structure of mantle discontinuities at the tip of the subducting slab beneath northeast China. J Phys Earth 44:701–711CrossRefGoogle Scholar
  20. O’Neill HStC, Palme H (1998) Composition of the silicate earth: implications for accretion and core formation. In: Jackson I (ed) The Earth’s mantle-composition, structure and evolution. Cambridge University Press, UK, pp 3–126Google Scholar
  21. Ovsyannikov S, Dubrovinsky L (2011) High-pressure high-temperature synthesis of Cr2O3 and Ga2O3. High Pres Res 31:23–29CrossRefGoogle Scholar
  22. Oxford Diffraction (2006) CrysAlis RED (Version and ABSPACK in CrysAlis RED. Oxford Diffraction Ltd, Abingdon, Oxfordshire, EnglandGoogle Scholar
  23. Panero WR, Akber-Knutson S, Stixrude L (2006) Al2O3 incorporation in MgSiO3 perovskite and ilmenite. Earth Plan Sci Lett 252:152–161CrossRefGoogle Scholar
  24. Reynard B, Rubie DC (1996) High-pressure, high-temperature Raman spectroscopic study of ilmenite type MgSiO3. Am Miner 81:1092–1096Google Scholar
  25. Reynard B, Fiquet G, Itie JP, Rubie DC (1996) High-pressure X-ray diffraction study and equation of state of MgSiO3 ilmenite. Am Miner 81:45–50Google Scholar
  26. Ringwood AE (1979) Origin of the earth and moon. Springer, New YorkCrossRefGoogle Scholar
  27. Robinson K, Gibbs GV, Ribbe PH (1971) Quadratic elongation: a quantitative measure of distortion in coordination polyhedra. Science 172:567–570CrossRefGoogle Scholar
  28. Sawamoto H (1987) Phase diagram of MgSiO3 at pressure up to 24 GPa and temperatures up to 2200 °C: Phase stability and properties of tetragonal garnet. In: Manghnai MH, Syono Y (eds) High-pressure research in mineral physics. American Geophysical Union, Washington, pp 209–219Google Scholar
  29. Sharp TG, Lingemann CM, Dupas C, Stöffler D (1997) Natural occurrence of MgSiO3-lmenite and evidence for MgSiO3-perovskite in a shocked L chondrite. Science 277:352–355CrossRefGoogle Scholar
  30. Sheldrick GM (2008) A short history of SHELX. Acta Crystallogr A64:112–122CrossRefGoogle Scholar
  31. Tomioka N, Fujino K (1997) Natural (Mg, Fe)SiO3-ilmenite and perovskite in the Tenham meteorite. Science 277:352–355CrossRefGoogle Scholar
  32. Tomioka N, Fujino K (1999) Akimotoite, (Mg, Fe)SiO3, a new silicate mineral of the ilmenite group in the Tenham chondrite. Am Miner 84:267–271Google Scholar
  33. Weidner DJ, Wang Y (1998) Chemical and Clapeyron induced buoyancy at the 660 km discontinuity. J Geophys Res 103:7431–7442CrossRefGoogle Scholar
  34. Yamada A, Inoue T, Irifune T (2004) Melting of enstatite from 13 to 18 GPa under hydrous conditions. Phys Earth Planet Inter 147:45–56CrossRefGoogle Scholar
  35. Yamanaka T, Komatsu Y, Sugahara M, Nagai T (2005) Structure change of MgSiO3, MgGeO3, and MgTiO3 ilmenites under compression. Am Miner 90:1301–1307CrossRefGoogle Scholar
  36. Zhang J, Weidner DJ (1999) Thermal equation of state of aluminum-enriched silicate perovskite. Science 284:782–784CrossRefGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2014

Authors and Affiliations

  • Luca Bindi
    • 1
    • 2
  • Ekaterina A. Sirotkina
    • 3
  • Andrey V. Bobrov
    • 3
  • Tetsuo Irifune
    • 4
    • 5
  1. 1.Dipartimento di Scienze della TerraUniversità di FirenzeFlorenceItaly
  2. 2.CNRIstituto di Geoscienze e Georisorse, sezione di FirenzeFlorenceItaly
  3. 3.Department of Petrology, Geological FacultyMoscow State UniversityMoscowRussia
  4. 4.Geodynamics Research CenterEhime UniversityMatsuyamaJapan
  5. 5.Earth-Life Science InstituteTokyo Institute of TechnologyTokyoJapan

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