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)
)O
3
E
´
rica G. Gravina, Jose
´
D. Ayala and Nelson G. Fernandes*
Department of Chemistry, Federal University of Minas Gerais, Av. Anto
ˆ
nio Carlos
6627, 31270-901 Belo Horizonte, Brazil
Received 16 July 2008; accepted 16 August 2008
Key indicators: single-crystal X-ray study; T = 298 K; mean () = 0.000 A
˚
; some non-
H atoms missing; disorder in main residue; R factor = 0.041; wR factor = 0.104; data-
to-parameter ratio = 51.4.
A natural sample of perovskite (calcium caesium sodium iron
titanium oxide) from the Tapira Alkaline Complex in south-
eastern Brazil was found by electron microprobe analysis to
have the chemical formula (Ca
2+
0.95 (1)
Ce
3+
0.011 (2)
Na
+
0.010 (4)
)-
(Fe
3+
0.022 (2)
Ti
4+
0.98 (1)
)O
2À
3
and by IR spectroscopy to be an
anhydrous mineral. Oxygen anions are arranged around Ti
4+
in an almost perfect octahedron and around Ca
2+
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 & Valenc¸a (1994); Soubies et al. (1991).
Experimental
Crystal data
Na
0.01
Ca
0.96
Fe
0.02
Ti
0.98
Ce
0.01
O
3
M
r
= 136.40
Orthorhombic, Pbnm
a = 5.3818 (4) A
˚
b = 5.4431 (4) A
˚
c = 7.6450 (5) A
˚
V = 223.95 (3) A
˚
3
Z =4
Mo K radiation
= 5.94 mm
À1
T = 298 (2) K
0.2 Â 0.15 Â 0.15 mm
Data collection
Siemens P4 diffractometer
Absorption correction: refined from
ÁF (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[F
2
>2(F
2
)] = 0.041
wR(F
2
) = 0.103
S = 1.25
1594 reflections
31 parameters
Á
max
= 2.01 e A
˚
À3
Á
min
= À2.88 e A
˚
À3
Table 1
Selected geometric parameters (A
˚
,
), where A represents the Ca
2+
,Na
+
and Ce
3+
cations, on a 12-coordinated site and B represents Fe
3+
and Ti
4+
cations on an octahedral site.
A—O
1
2.359 (2) O
1
iv
—A—O
1
iv
162.30 (6)
A—O
1
iv
2.481 (2) O
2
iv
—A—O
2
viii
80.97 (4)
A—O
1
iv
3.027 (2) O
1
—A—O
2
vii
118.03 (2)
A—O
1
3.052 (2) O
2
ii
—A—O
1
iv
65.08 (3)
A—O
2
viii
2.378 (1)
A—O
2
ii
2.620 (1)
A—O
2
iv
2.667 (1)
A—O
2
vi
3.233 (1)
B—O
1
ii
1.9513 (3) O
1
—B—O
1
ii
180.0
B—O
2
vii
1.956 (1) O
2
—B—O
2
vii
89.41 (1)
B—O
2
v
1.959 (1) O
1
—B—O
2
89.58 (6)
Symmetry code: (ii) Àx; Ày; z þ
1
2
; (iii) ðx þ
1
2
ÞÀ1; Ày þ
1
2
; Àz; (iv)
Àx þ
1
2
; ðy þ
1
2
ÞÀ1; 1 ÀðÀz þ
1
2
Þ; (v) Àx; Ày; Àz; (vi) x; y; 1 ÀðÀz þ
1
2
Þ; (vii)
Àx þ
1
2
; y þ
1
2
; z ; (viii) ðx þ
1
2
ÞÀ1; Ày þ
1
2
; z þ
1
2
; (ix) Àx; Ày þ 1; ðz þ
1
2
ÞÀ1.
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: Crys-
talMaker (CrystalMaker, 2007); software used to prepare material for
publication: WinGX (Farrugia, 1999).
The authors are grateful to Dr Jose
´
Affonso Brod,
University of Brası
´
lia, 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, FAPEM IG (Grant
CEX 1123/90). EGG is grateful to the Brazilian Science
Research Council, CNPq, for providing a graduate fellowship.
Supplementary data and figures for this paper are available from the
IUCr electronic archives (Reference: MG2053).
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. Araxa
´
, 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, Ru
´
ssia, pp. 498–499.
Sgarbi, P. B. A. & Valenc¸a, J. G. (1994). International Symposium on the
Physics and Chemistry of the Upper Mantle (Extended Abstracts), pp. 27–
29. Sa
˜
o Paulo, Brazil: CPRM/FAPESP.
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122.
Siemens (1991). XSCANS User’s Manual. Siemens Analytical X-ray Instru-
ments Inc., Madison, Wisconsin, USA.
Soubies, F., Melfi, A. J. & Autefage, F. (1991). Rev. Bras. Geo. 21, 3-16.
inorganic compounds
Acta Cryst. (2008). E64, i65 doi:10.1107/S1600536808026421 Gravina et al. i65
Acta Crystallographica Section E
Structure Reports
Online
ISSN 1600-5368