Natural perovskite: (CaII0.95 (1)CeIII0.011 (2)NaI0.010 (4))(FeIII0.022 (2)TiIV0.98 (1))O3

Gravina, É.G.; Ayala, J.D.; Fernandes, N.G.

doi:10.1107/S1600536808026421

Volume 64
Part 9
Page i65
September 2008

Received 16 July 2008
Accepted 16 August 2008
Online 30 August 2008

Key indicators
Single-crystal X-ray study
T = 298 K
Mean () = 0.000 Å
Some non-H atoms missing,
Disorder in main residue
R = 0.041
wR = 0.104
Data-to-parameter ratio = 51.4
Details

Natural perovskite: (Ca^II_0.95 (1)Ce^III_0.011 (2)Na^I_0.010 (4))(Fe^III_0.022 (2)Ti^IV_0.98 (1))O₃

Érica G. Gravina,^a José D. Ayala ^a and Nelson G. Fernandes ^a ^*

^aDepartment of Chemistry, Federal University of Minas Gerais, Av. Antônio Carlos 6627, 31270-901 Belo Horizonte, Brazil
Correspondence e-mail: ngfernandes@ufmg.br

A natural sample of perovskite (calcium caesium sodium iron titanium oxide) from the Tapira Alkaline Complex in southeastern Brazil was found by electron microprobe analysis to have the chemical formula (Ca²⁺_0.95 (1)Ce³⁺_0.011 (2)Na⁺_0.010 (4))(Fe³⁺_0.022 (2)Ti⁴⁺_0.98 (1))O^2-₃ and by IR spectroscopy to be an anhydrous mineral. Oxygen anions are arranged around Ti⁴⁺ in an almost perfect octahedron and around Ca²⁺ in a distorted 12-fold polyhedron.

Related literature

For related literature, see: Banfield & Veblen (1992); Beran et al. (1996); Chakhmouradian & Mitchell (1998); Haggerty & Mariano (1983); Kay & Bailey (1957); Lloyd & Bailey (1991); Mariano & Mitchell (1991); Seer & Moraes (1988); Sgarbi & Gaspar (1995); Sgarbi & Valença (1994); Soubies et al. (1991).

Experimental

Crystal data

Na_0.01Ca_0.96Fe_0.02Ti_0.98Ce_0.01O₃
M_r = 136.40
Orthorhombic, P b n m
a = 5.3818 (4) Å
b = 5.4431 (4) Å
c = 7.6450 (5) Å
V = 223.95 (3) Å³
Z = 4
Mo K radiation
= 5.94 mm^-1
T = 298 (2) K
0.2 × 0.15 × 0.15 mm

Data collection

Siemens P4 diffractometer
Absorption correction: refined from F (SHELXL97; Sheldrick, 2008) T_min = 0.356, T_max = 0.409
2383 measured reflections
1594 independent reflections
1527 reflections with I > 2s(I)
R_int = 0.033
3 standard reflections every 197 reflections intensity decay: 0.8%

Refinement

R[F² > 2(F²)] = 0.041
wR(F²) = 0.103
S = 1.25
1594 reflections
31 parameters
_max = 2.01 e Å^-3
_min = -2.88 e Å^-3

Table 1
Selected geometric parameters (Å ,° ), where A represents the Ca²⁺, Na⁺ and Ce³⁺ cations, on a 12-coordinated site and B represents Fe³⁺ and Ti⁴⁺ cations on an octahedral site

A-O₁	2.359 (2)	O₁^iv-A-O₁^iv	162.30 (6)
A-O₁^iv	2.481 (2)	O₂^iv-A-O₂^viii	80.97 (4)
A-O₁^iv	3.027 (2)	O₁-A-O₂^vii	118.03 (2)
A-O₁	3.052 (2)	O₂ⁱⁱ-A-O₁^iv	65.08 (3)
A-O₂^viii	2.378 (1)
A-O₂ⁱⁱ	2.620 (1)
A-O₂^iv	2.667 (1)
A-O₂^vi	3.233 (1)
B-O₁ⁱⁱ	1.9513 (3)	O₁-B-O₁ⁱⁱ	180.0
B-O₂^vii	1.956 (1)	O₂-B-O₂^vii	89.41 (1)
B-O₂^v	1.959 (1)	O₁-B-O₂	89.58 (6)
Symmetry code: (ii) $[-x, -y, z + {\script{1\over 2}}]$ ; (iii) $[(x + {\script{1\over 2}}) -1, -y + {\script{1\over 2}}, -z]$ ; (iv) $[-x + {\script{1\over 2}}, (y + {\script{1\over 2}}) - 1, 1- (-z + {\script{1\over 2}})]$ ; (v) -x, -y, -z; (vi) $[x, y, 1 - (-z + {\script{1\over 2}})]$ ; (vii) $[-x + {\script{1\over 2}}, y + {\script{1\over 2}}, z]$ ; (viii) $[(x + {\script{1\over 2}}) - 1, -y + {\script{1\over 2}}, z + {\script{1\over 2}}]$ ; (ix) $[-x, -y + 1, (z + {\script{1\over 2}}) -1]$ .

Data collection: XSCANS (Siemens, 1991); cell refinement: XSCANS; data reduction: XSCANS; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: CrystalMaker (CrystalMaker, 2007); software used to prepare material for publication: WinGX (Farrugia, 1999).

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: MG2053 ).

Acknowledgements

The authors are grateful to Dr José Affonso Brod, University of Brasília, Brazil, for providing the perovskite samples, and to Mr William T. Soares for the microprobe analysis. This work was supported by the Minas Gerais Foundation for Research Development, FAPEMIG (Grant CEX 1123/90). EGG is grateful to the Brazilian Science Research Council, CNPq, for providing a graduate fellowship.

References

Banfield, J. F. & Veblen, D. R. (1992). Am. Mineral. 77, 545-557.
Beran, A., Libowittzky, E. & Armbruster, T. (1996). Can. Mineral. 34, 803-809.
Chakhmouradian, A. R. & Mitchell, R. H. (1998). Can. Mineral. 36, 953-969.
CrystalMaker (2007). CrystalMaker for Windows. CrystalMaker Software Ltd, Yarnton, England.
Farrugia, L. J. (1999). J. Appl. Cryst. 32, 837-838.
Haggerty, S. E. & Mariano, A. N. (1983). Contrib. Mineral. Petrol. 84, 365-381.
Kay, H. F. & Bailey, P. C. (1957). Acta Cryst. 10, 219-226.
Lloyd, F. E. & Bailey, D. K. (1991). 5th International Kimberlite Conference (Extended Abstracts), edited by O. H. Leonardos, H. O. A. Meyer & J. C. Gaspar, pp. 263-269. Araxá, Brazil, CPRM, Special Publication 3/91.
Mariano, A. N. & Mitchell, R. H. (1991). Proceedings of the 5th International Conference, Araxa, Brazil, pp. 251-253. Extended Abstracts.
Seer, H. J. & Moraes, L. C. (1988). Rev. Bras. Geo. 18, 134-140.
Sgarbi, P. B. A. & Gaspar, J. C. (1995). 6th International Kimberlite Conference (Extended Abstracts), Novosibirsk, Rússia, pp. 498-499.
Sgarbi, P. B. A. & Valença, J. G. (1994). International Symposium on the Physics and Chemistry of the Upper Mantle (Extended Abstracts), pp. 27-29. São Paulo, Brazil: CPRM/FAPESP.
Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.
Siemens (1991). XSCANS User's Manual. Siemens Analytical X-ray Instruments Inc., Madison, Wisconsin, USA.
Soubies, F., Melfi, A. J. & Autefage, F. (1991). Rev. Bras. Geo. 21, 3-16.

inorganic compounds