Tripraseodymium penta­iron(III) dodeca­oxide, Pr3Fe5O12: a synchrotron radiation study

Komori, T.; Sakakura, T.; Takenaka, Y.; Tanaka, K.; Okuda, T.

doi:10.1107/S1600536809038100

inorganic compounds

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Volume 65| Part 11| November 2009| Page i73

https://doi.org/10.1107/S1600536809038100

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Tripraseodymium pentairon(III) dodecaoxide, Pr₃Fe₅O₁₂: a synchrotron radiation study

Takashi Komori,^a ^* Terutoshi Sakakura,^a Yasuyuki Takenaka,^b Kiyoaki Tanaka ^a and Takashi Okuda ^a

^aGraduate School of Materials Science and Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Japan, and ^bHokkaido University of Education HAKODATE, Yahata-cho, Hakodate-shi, Japan
^*Correspondence e-mail: tkomori@katch.ne.jp

(Received 14 September 2009; accepted 21 September 2009; online 3 October 2009)

The title compound, pentairon tripraseodymium dodecaoxide (PrIG), has an iron garnet structure. There are two Fe site symmetries. One of the Fe atoms is coordinated by six O atoms, forming a slightly distorted octahedron, and has $[\overline{3}]$ site symmetry. The other Fe atom is coordinated by four O atoms, forming a slightly distorted tetrahedron, and has $[\overline{4}]$ site symmetry. FeO₆ octahedra and FeO₄ tetrahedra are linked together by corners. The Pr atom is coordinated by eight O atoms, forming a distorted dodecahedron, and has 222 site symmetry. The O atoms occupy the general positions.

Related literature

The title compound is isotypic with the Ia $[\overline{3}]$ d form of Y₃Fe₅O₁₂ (YIG). For related structures, see: Bonnet et al. (1975 ). For details of the crystal growth from low-temperature liquid-phase epitaxy, see: Fratello et al. (1986 ). For the extinction correction, see: Becker & Coppens (1975 ). X-ray intensities were measured avoiding multiple diffraction, see: Takenaka et al. (2008 ).

Experimental

Crystal data

Pr₃Fe₅O₁₂
M_r = 893.98
Cubic, $[I a \overline 3d ]$
a = 12.6302 (3) Å
V = 2014.79 (8) Å³
Z = 8
Synchrotron radiation
λ = 0.67171 Å
μ = 17.41 mm⁻¹
T = 298 K
0.035 mm (radius)

Data collection

Rigaku AFC four-circle diffractometer
Absorption correction: for a sphere [transmission coefficients for spheres tabulated in International Tables C (1992), Table 6.3.3.3, were interpolated with Lagrange's method (four-point interpolation; Yamauchi et al., 1965 )] T_min = 0.413, T_max = 0.441
9351 measured reflections
1728 independent reflections
1728 reflections with F > 3σ(F)
R_int = 0.016

Refinement

R[F² > 2σ(F²)] = 0.019
wR(F²) = 0.021
S = 1.06
9351 reflections
17 parameters
Δρ_max = 2.52 e Å⁻³
Δρ_min = −3.16 e Å⁻³

Table 1
Selected geometric parameters (Å, °)

Pr1—O1	2.42410 (10)
Pr1—O1ⁱ	2.54010 (10)
Fe1—O1	2.03220 (10)
Fe2—O1ⁱⁱ	1.87450 (10)

O1—Fe1—O1ⁱ	85.87 (1)
O1ⁱⁱ—Fe2—O1ⁱⁱⁱ	114.39 (1)
O1ⁱⁱ—Fe2—O1^iv	100.02 (1)
Symmetry codes: (i) z, x, y; (ii) $[x+{\script{1\over 2}}, y, -z+{\script{1\over 2}}]$ ; (iii) $[-x+{\script{1\over 4}}, z-{\script{1\over 4}}, y+{\script{1\over 4}}]$ ; (iv) $[x+{\script{1\over 2}}, -y, z]$ .

Data collection: AFC-5, specially designed for PF-BL14A (Rigaku, 1984 ) and IUANGLE (Tanaka et al., 1994 ); cell refinement: RSLC-3 UNICS system (Sakurai & Kobayashi, 1979 ); data reduction: RDEDIT (Tanaka, 2008 ); program(s) used to solve structure: QNTAO (Tanaka et al., 2008 ); program(s) used to refine structure: QNTAO; molecular graphics: ATOMS for Windows (Dowty, 2000 ); software used to prepare material for publication: RDEDIT.

Supporting information

Crystal structure: contains datablocks global, I. DOI: https://doi.org/10.1107/S1600536809038100/br2121sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536809038100/br2121Isup2.hkl

checkCIF report

Comment top

The title compound, Pr₃Fe₅O₁₂ (PrIG), was difficult to be grown. It was grown by the low-temperature-liquid-phase epitaxy for the first time by Fratello et al. (1986). Though the crystal structure was assumed as iron-garnet-type structure by lattice constant and extinction rule, the complete structure was not determined. In this paper, we determine the O atom position and the complete structure by the full matrix least-squares program QNTAO. Since the R-factor is small and the residual density has no significant peaks where no atoms exists, the structure was finally determined to be iron-garnet structure. It is isotypic with the Ia3d form of Y₃Fe₅O₁₂ (YIG). (Bonnet et al., 1975). The Pr atom is coordinated by eight oxygen atoms. It forms a distorted dodecahedron. There are two Fe site symmetries. One of the Fe atom is coordinated by six oxygen atoms. It forms a slitely distorted octahedron. The other Fe atom is coordinated by four oxygen atoms. It forms a slightly distorted tetrahedron. FeO₆ octahedron and FeO₄ tetrahedron are linked together by corners. The structure of PrIG is drawn in Fig.1. And displacement ellipsoids of PrO₈ is drawn in Fig.2.

Related literature top

The title compound is isotypic with the Ia3d form of Y₃Fe₅O₁₂ (YIG). For related structures, see : Bonnet et al. (1975). For details of the crystal growth from low-temperature liquid-phase epitaxy, see: Fratello et al. (1986).

For related literature, see: Becker & Coppens (1975); Takenaka et al. (2008).

Experimental top

Single crystals of praseodymium iron garnet were prepared by low temperature liquid phase epitaxy on Sm₃(ScGa)₅O₁₂ seeds with lattice parameters near the projected values for PrIG.

Structure description top

For related literature, see: Becker & Coppens (1975); Takenaka et al. (2008).

Computing details top

Data collection: AFC-5, specially designed for PF-BL14A (Rigaku, 1984) and IUANGLE (Tanaka et al., 1994).; cell refinement: RSLC-3 UNICS system (Sakurai & Kobayashi, 1979); data reduction: RDEDIT (Tanaka, 2008); program(s) used to solve structure: QNTAO (Tanaka et al., 2008); program(s) used to refine structure: QNTAO (Tanaka et al., 2008); molecular graphics: ATOMS for Windows (Dowty, 2000); software used to prepare material for publication: RDEDIT (Tanaka, 2008).

Figures top

	Fig. 1. The structure of Pr₃Fe₅O₁₂. Small red and large green spheres represent O and Pr atoms, respectively. Purple octahedron and blue tetrahedron represent FeO₆ and FeO₄ units, respectively.
	Fig. 2. View of PrO₈ with displacement ellipsoids at the 90% probability level. Green and red ellipsoids represent Pr and O atoms, in Fig.1.

Pentairon tripraseodymium dodecaoxide top

Crystal data top

Pr₃Fe₅O₁₂	D_x = 5.894 Mg m⁻³
M_r = 893.98	Synchrotron radiation, λ = 0.67171 Å
Cubic, Ia3d	Cell parameters from 9 reflections
Hall symbol: -I 4bd 2c 3	θ = 17.5–52.3°
a = 12.6302 (3) Å	µ = 17.41 mm⁻¹
V = 2014.79 (8) Å³	T = 298 K
Z = 8	Sphere, black
F(000) = 3224	0.04 mm (radius)

Data collection top

Rigaku AFC four-circle diffractometer	1728 independent reflections
Si 111 monochromator	1728 reflections with F > 3σ(F)
Detector resolution: 1.25 × 1.25° pixels mm^-1	R_int = 0.016
ω/2θ scans	θ_max = 68.3°, θ_min = 3.7°
Absorption correction: for a sphere [Transmission coefficients for spheres tabulated in International Tables C (1992), Table 6.3.3.3, were interpolated with Lagrange's method (four-point interpolation (Yamauchi et al., 1965)]	h = −9→34
T_min = 0.413, T_max = 0.441	k = −9→32
9351 measured reflections	l = −9→34

Refinement top

Refinement on F	Primary atom site location: isomorphous structure methods
Least-squares matrix: full	Weighting scheme based on measured s.u.'s
R[F² > 2σ(F²)] = 0.019	(Δ/σ)_max = 0.003
wR(F²) = 0.021	Δρ_max = 2.52 e Å⁻³
S = 1.06	Δρ_min = −3.16 e Å⁻³
9351 reflections	Extinction correction: B–C type 1 Gaussian isotropic (Becker & Coppens, 1975)
17 parameters	Extinction coefficient: 0.255 (5)

Crystal data top

Pr₃Fe₅O₁₂	Z = 8
M_r = 893.98	Synchrotron radiation, λ = 0.67171 Å
Cubic, Ia3d	µ = 17.41 mm⁻¹
a = 12.6302 (3) Å	T = 298 K
V = 2014.79 (8) Å³	0.04 mm (radius)

Data collection top

Rigaku AFC four-circle diffractometer	1728 independent reflections
Absorption correction: for a sphere [Transmission coefficients for spheres tabulated in International Tables C (1992), Table 6.3.3.3, were interpolated with Lagrange's method (four-point interpolation (Yamauchi et al., 1965)]	1728 reflections with F > 3σ(F)
T_min = 0.413, T_max = 0.441	R_int = 0.016
9351 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.019	17 parameters
wR(F²) = 0.021	Δρ_max = 2.52 e Å⁻³
S = 1.06	Δρ_min = −3.16 e Å⁻³
9351 reflections

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
Pr1	0.125000	0.000000	0.250000	0.00531 (1)
Fe1	0.000000	0.000000	0.000000	0.00512 (1)
Fe2	0.375000	0.000000	0.250000	0.00533 (1)
O1	−0.029622 (2)	0.052553 (2)	0.149166 (2)	0.00711 (5)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Pr1	0.00406 (2)	0.00594 (2)	0.00594 (2)	0	0	0.00111 (1)
Fe1	0.00512 (2)	0.00512 (2)	0.00512 (2)	−0.00023 (1)	−0.00023 (1)	−0.00023 (1)
Fe2	0.00411 (3)	0.00594 (2)	0.00594 (2)	0	0	0
O1	0.00718 (8)	0.00829 (8)	0.00587 (7)	−0.00004 (6)	0.00080 (6)	0.00038 (6)

Geometric parameters (Å, º) top

Pr1—O1	2.4241 (1)	Fe1—O1ⁱ	2.0322 (1)
Pr1—O1ⁱ	2.5401 (1)	Fe1—O1^viii	2.0322 (1)
Pr1—O1ⁱⁱ	2.4241 (1)	Fe1—O1^ix	2.0322 (1)
Pr1—O1ⁱⁱⁱ	2.5401 (1)	Fe1—O1^x	2.0322 (1)
Pr1—O1^iv	2.4241 (1)	Fe1—O1^xi	2.0322 (1)
Pr1—O1^v	2.5401 (1)	Fe2—O1^xii	1.8745 (1)
Pr1—O1^vi	2.4241 (1)	Fe2—O1^iv	1.8745 (1)
Pr1—O1^vii	2.5401 (1)	Fe2—O1^xiii	1.8745 (1)
Fe1—O1	2.0322 (1)	Fe2—O1^vi	1.8745 (1)

O1—Pr1—O1ⁱ	67.75 (1)	O1—Fe1—O1^viii	85.87 (1)
O1—Pr1—O1ⁱⁱ	72.66 (1)	O1—Fe1—O1^ix	180.00
O1—Pr1—O1ⁱⁱⁱ	124.91 (1)	O1—Fe1—O1^x	94.13 (1)
O1—Pr1—O1^iv	111.18 (1)	O1—Fe1—O1^xi	94.13 (1)
O1—Pr1—O1^v	73.25 (1)	O1^xii—Fe2—O1^vi	114.39 (1)
O1—Pr1—O1^vi	159.51 (1)	O1^xii—Fe2—O1^iv	114.39 (1)
O1—Pr1—O1^vii	95.43 (1)	O1^xii—Fe2—O1^xiii	100.02 (1)
O1—Fe1—O1ⁱ	85.87 (1)

Symmetry codes: (i) z, x, y; (ii) x, −y, −z+1/2; (iii) z, −x, −y+1/2; (iv) −x+1/4, −z+1/4, −y+1/4; (v) −z+1/4, −y+1/4, −x+1/4; (vi) −x+1/4, z−1/4, y+1/4; (vii) −z+1/4, y−1/4, x+1/4; (viii) y, z, x; (ix) −x, −y, −z; (x) −z, −x, −y; (xi) −y, −z, −x; (xii) x+1/2, y, −z+1/2; (xiii) x+1/2, −y, z.

Experimental details

Crystal data
Chemical formula	Pr₃Fe₅O₁₂
M_r	893.98
Crystal system, space group	Cubic, Ia3d
Temperature (K)	298
a (Å)	12.6302 (3)
V (Å³)	2014.79 (8)
Z	8
Radiation type	Synchrotron, λ = 0.67171 Å
µ (mm⁻¹)	17.41
Crystal size (mm)	0.04 (radius)

Data collection
Diffractometer	Rigaku AFC four-circle
Absorption correction	For a sphere [Transmission coefficients for spheres tabulated in International Tables C (1992), Table 6.3.3.3, were interpolated with Lagrange's method (four-point interpolation (Yamauchi et al., 1965)]
T_min, T_max	0.413, 0.441
No. of measured, independent and observed [F > 3σ(F)] reflections	9351, 1728, 1728
R_int	0.016
(sin θ/λ)_max (Å⁻¹)	1.383

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.019, 0.021, 1.06
No. of reflections	9351
No. of parameters	17
No. of restraints	?
Δρ_max, Δρ_min (e Å⁻³)	2.52, −3.16

Computer programs: AFC-5, specially designed for PF-BL14A (Rigaku, 1984) and IUANGLE (Tanaka et al., 1994)., RSLC-3 UNICS system (Sakurai & Kobayashi, 1979), RDEDIT (Tanaka, 2008), QNTAO (Tanaka et al., 2008), ATOMS for Windows (Dowty, 2000).

Selected geometric parameters (Å, º) top

Pr1—O1	2.4241 (1)	Fe1—O1	2.0322 (1)
Pr1—O1ⁱ	2.5401 (1)	Fe2—O1ⁱⁱ	1.8745 (1)

O1—Fe1—O1ⁱ	85.87 (1)	O1ⁱⁱ—Fe2—O1^iv	100.02 (1)
O1ⁱⁱ—Fe2—O1ⁱⁱⁱ	114.39 (1)

Symmetry codes: (i) z, x, y; (ii) x+1/2, y, −z+1/2; (iii) −x+1/4, z−1/4, y+1/4; (iv) x+1/2, −y, z.

Acknowledgements

The authors thank Dr V. J. Fratello for supplying the crystals.

References

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