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Perovskite

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This article is about the mineral. For synthetic compounds, see Perovskite (structure).
Perovskite
Crystals of perovskite on matrix
Size: 2.3 cm × 2.1 cm × 2.0 cm (0.9 in × 0.8 in × 0.8 in)
General
CategoryOxide minerals
Formula
(repeating unit)		CaTiO3
IMA symbolPrv[1]
Strunz classification4.CC.30
Crystal systemOrthorhombic
Crystal classDipyramidal (mmm)
H-M symbol: (2/m 2/m 2/m)
Space groupPbnm
Identification
Formula mass135.96 g/mol
ColorBlack, reddish brown, pale yellow, yellowish orange
Crystal habitPseudo cubic – crystals show a cubic outline
Twinningcomplex penetration twins
Cleavage[100] good, [010] good, [001] good
FractureConchoidal
Mohs scale hardness5.0–5.5
LusterAdamantine to metallic; may be dull
Streakgrayish white
DiaphaneityTransparent to opaque
Specific gravity3.98–4.26
Optical propertiesBiaxial (+)
Refractive indexnα = 2.3, nβ = 2.34, nγ = 2.38
Other characteristicsnon-radioactive, non-magnetic
References[2][3][4][5]

Perovskite (pronunciation: /pəˈrɒvskaɪt/) is a calcium titanium oxide mineral composed of calcium titanate (chemical formula CaTiO3). Its name is also applied to the class of compounds which have the same type of crystal structure as CaTiO3, known as the perovskite structure, which has a general chemical formula A2+B4+(X2−)3.[6] Many different cations can be embedded in this structure, allowing the development of diverse engineered materials.[7]

History

The mineral was discovered in the Ural Mountains of Russia by Gustav Rose in 1839 and is named after Russian mineralogist Lev Perovski (1792–1856).[3] Perovskite's notable crystal structure was first described by Victor Goldschmidt in 1926 in his work on tolerance factors.[8] The crystal structure was later published in 1945 from X-ray diffraction data on barium titanate by Helen Dick Megaw.[9]

Occurrence

Found in the Earth's mantle, perovskite's occurrence at Khibina Massif is restricted to the silica under-saturated ultramafic rocks and foidolites, due to the instability in a paragenesis with feldspar. Perovskite occurs as small anhedral to subhedral crystals filling interstices between the rock-forming silicates.[10]

Perovskite is found in contact carbonate skarns at Magnet Cove, Arkansas, in altered blocks of limestone ejected from Mount Vesuvius, in chlorite and talc schist in the Urals and Switzerland,[11] and as an accessory mineral in alkaline and mafic igneous rocks, nepheline syenite, melilitite, kimberlites and rare carbonatites. Perovskite is a common mineral in the Ca-Al-rich inclusions found in some chondritic meteorites.[4]

The stability of perovskite in igneous rocks is limited by its reaction relation with sphene. In volcanic rocks perovskite and sphene are not found together, the only exception being an etindite from Cameroon.[12]

A rare-earth-bearing variety knopite with the chemical formula (Ca,Ce,Na)(Ti,Fe)O3 is found in alkali intrusive rocks in the Kola Peninsula and near Alnö, Sweden. A niobium-bearing variety dysanalyte occurs in carbonatite near Schelingen, Kaiserstuhl, Germany.[11][13]

In stars and brown dwarfs

In stars and brown dwarfs the formation of perovskite grains is responsible for the depletion of titanium oxide in the photosphere. Stars with a low temperature have dominant bands of TiO in their spectrum; as the temperature gets lower for stars and brown dwarfs with an even lower mass, CaTiO3 forms and at temperatures below 2000 K TiO is undetectable. The presence of TiO is used to define the transition between cool M-dwarf stars and the colder L-dwarfs.[14][15]

Physical properties

Crystal structure of perovskite CaTiO3; red=oxygen, grey=titanium, blue=calcium

The eponymous Perovskite CaTiO3 crystallizes in the Pbnm space group (No. 62) with lattice constants a = 5.39 Å, b = 5.45 Å and c = 7.65 Å.[16]

Perovskites have a nearly cubic structure with the general formula ABO3. In this structure the A-site ion, in the center of the lattice, is usually an alkaline earth or rare-earth element. B-site ions, on the corners of the lattice, are 3d, 4d, and 5d transition metal elements. The A-site cations are in 12-fold coordination with the anions, while the B-site cations are in 6-fold coordination. A large number of metallic elements are stable in the perovskite structure if the Goldschmidt tolerance factor t is in the range of 0.75 to 1.0.[17]

where RA, RB and RO are the ionic radii of A and B site elements and oxygen, respectively. The stability of perovskites can be characterized with the tolerance and octahedral factors. When conditions are not fulfilled, a layered geometry for edge-sharing or face-sharing octahedra or lower B-site coordination is preferred. These are good structural bounds, but not an empirical prediction.[18]

Perovskites have sub-metallic to metallic luster, colorless streak, and cube-like structure along with imperfect cleavage and brittle tenacity. Colors include black, brown, gray, orange to yellow. Perovskite crystals may appear to have the cubic crystal form, but are often pseudocubic and actually crystallize in the orthorhombic system, as is the case for CaTiO3 (strontium titanate, with the larger strontium cation in the A-site, is cubic). Perovskite crystals have been mistaken for galena; however, galena has a better metallic luster, greater density, perfect cleavage and true cubic symmetry.[19]

Perovskite derivatives

Double perovskites

A double perovskite has a formula of A'A"B'B"O6 and replaces half the B sites with B′, where A are alkaline or rare earth metals and B are transition metals. The cation arrangement will differ based on charge, coordination geometry, and the ratio between A cation and B cation radii. The B and B′ cations lead to different ordering schemes. These ordering schemes are rock salt, columnar, and layered structures.[20] Rock salt is an alternating, three-dimensional checkerboard of B and B' polyhedra. This structure is the most common from an electrostatic point of view, as the B sites will have different valence states. Columnar arrangement can be viewed as sheets of B-cation polyhedral viewed from the [111] direction. Layered structures are seen as sheets of B′ and B polyhedra.

Lower dimensional perovskites

3D perovskites form when there is a smaller cation in the A site so BX6 octahedra can be corner shared. 2D perovskites form when the A-site cation is larger so octahedra sheets are formed. In 1D perovskites, a chain of octahedra is formed[21] while in 0D perovskites, individual octahedra are separated from each other. Both 1D and 0D perovskites lead to quantum confinement[22] and are investigated for lead-free perovskite solar cell materials.[23]

See also

References

  1. ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
  2. ^ "Prehnit (Prehnite)". Mineralienatlas.de.
  3. ^ a b "Perovskite". Webmineral.
  4. ^ a b Anthony, John W.; Bideaux, Richard A.; Bladh, Kenneth W.; Nichols, Monte C. (eds.). "Perovskite" (PDF). Handbook of Mineralogy. Chantilly, VA: Mineralogical Society of America.
  5. ^ Inoue, Naoki; Zou, Yanhui (2006). "Physical properties of perovskite-type lithium ionic conductor" (PDF). In Sakuma, Takashi; Takahashi, Haruyuki (eds.). Physics of Solid State Ionics. pp. 247–269. ISBN 978-81-308-0070-7.
  6. ^ Wenk, Hans-Rudolf; Bulakh, Andrei (2004). Minerals: Their Constitution and Origin. New York: Cambridge University Press. p. 413. ISBN 978-0-521-52958-7.
  7. ^ Szuromi, Phillip; Grocholski, Brent (2017). "Natural and engineered perovskites". Science. 358 (6364): 732–733. Bibcode:2017Sci...358..732S. doi:10.1126/science.358.6364.732. PMID 29123058.
  8. ^ Golschmidt, V. M. (1926). "Die Gesetze der Krystallochemie". Die Naturwissenschaften. 14 (21): 477–485. Bibcode:1926NW.....14..477G. doi:10.1007/BF01507527. S2CID 33792511.
  9. ^ Megaw, Helen (1945). "Crystal Structure of Barium Titanate". Nature. 155 (3938): 484–485. Bibcode:1945Natur.155..484.. doi:10.1038/155484b0. S2CID 4096136.
  10. ^ Chakhmouradian, Anton R.; Mitchell, Roger H. (1998). "Compositional variation of perovskite-group minerals from the Khibina Complex, Kola Peninsula, Russia" (PDF). The Canadian Mineralogist. 36: 953–969.
  11. ^ a b Palache, Charles, Harry Berman and Clifford Frondel, 1944, Dana's System of Mineralogy Vol. 1, Wiley, 7th ed. p. 733
  12. ^ Veksler, I. V.; Teptelev, M. P. (1990). "Conditions for crystallization and concentration of perovskite-type minerals in alkaline magmas". Lithos. 26 (1): 177–189. Bibcode:1990Litho..26..177V. doi:10.1016/0024-4937(90)90047-5.
  13. ^ Deer, William Alexander; Howie, Robert Andrew; Zussman, J. (1992). An introduction to the rock-forming minerals. Longman Scientific Technical. ISBN 978-0-582-30094-1.
  14. ^ Allard, France; Hauschildt, Peter H.; Alexander, David R.; Tamanai, Akemi; Schweitzer, Andreas (July 2001). "The Limiting Effects of Dust in Brown Dwarf Model Atmospheres". Astrophysical Journal. 556 (1): 357–372. arXiv:astro-ph/0104256. Bibcode:2001ApJ...556..357A. doi:10.1086/321547. ISSN 0004-637X. S2CID 14944231.
  15. ^ Kirkpatrick, J. Davy; Allard, France; Bida, Tom; Zuckerman, Ben; Becklin, E. E.; Chabrier, Gilles; Baraffe, Isabelle (July 1999). "An Improved Optical Spectrum and New Model FITS of the Likely Brown Dwarf GD 165B". Astrophysical Journal. 519 (2): 834–843. Bibcode:1999ApJ...519..834K. doi:10.1086/307380. ISSN 0004-637X.
  16. ^ Buttner, R. H.; Maslen, E. N. (1992-10-01). "Electron difference density and structural parameters in CaTiO3". Acta Crystallographica Section B: Structural Science. 48 (5): 644–649. doi:10.1107/S0108768192004592. ISSN 0108-7681.
  17. ^ Peña, M. A.; Fierro, J. L. (2001). "Chemical structures and performance of perovskite oxides" (PDF). Chemical Reviews. 101 (7): 1981–2017. doi:10.1021/cr980129f. PMID 11710238.[permanent dead link]
  18. ^ Filip, Marina; Giustino, Feliciano (2018). "The Geometric Blueprint of Perovskites". Proceedings of the National Academy of Sciences. 115 (21): 5397–5402. arXiv:1805.08250. Bibcode:2018PNAS..115.5397F. doi:10.1073/pnas.1719179115. PMC 6003477. PMID 29735683.
  19. ^ Luxová, Jana; Šulcová, Petra; Trojan, M. (2008). "Study of Perovskite" (PDF). Journal of Thermal Analysis and Calorimetry. 93 (3): 823–827. doi:10.1007/s10973-008-9329-z. S2CID 97682597.
  20. ^ Saha-Dasgupta, Tanusri (2001). "Double perovskites with 3d and 4d/5d transition metals: compounds with promises". Materials Research Express. 101 (7): 1981–2017. doi:10.1088/2053-1591/ab6293. S2CID 214470882.
  21. ^ Trifiletti, Vanira (2021). "Quasi-Zero dimensional Halide Perovskite Derivatives: Synthesis, Status, and Opportunity". Frontiers in Electronics. 2. doi:10.3389/felec.2021.758603.
  22. ^ Zhang, Zhipeng (2021). "Metal Halide Perovskite/2D Material Heterostructures: Syntheses and Applications". Materials Research Express. 5 (4): e2000937. doi:10.1002/smtd.202000937. PMID 34927847. S2CID 234172920.
  23. ^ Gao, Yuting (2021). "Lead-free halide perovskites: a review of the structure–property relationship and applications in light emitting devices and radiation detectors". Journal of Materials Chemistry A. 9 (20): 11931–11943. doi:10.1039/d1ta01737c. S2CID 236391984.
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