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Structural analysis of anion-rich C-type Gd2O3 was carried by the Rietveld refinement of the powder X-ray diffraction data for compositions Gd0.8Ce0.2O1.60 and Gd0.6Ce0.4O1.70. Both compounds have a body-centred cubic lattice (space group Ia\bar{3}, No. 206, Z = 32) with unit-cell parameters of 10.8488 (1) and 10.8542 (1) Å, respectively. Both of these compounds are iso-structural with the C-type rare earth oxides, with excess anions as required for charge balance. The structural analysis reveals that there are two different kinds of metal ion site, namely 8b (M1) and 24d (M2), and two different kinds of anion sites, namely 48e (O1) and 16c (O2). The excess anions occupy the 16c (xxx) sites. The two metal ions each form an approximately eightfold-coordination polyhedron with O1 and O2. The details of these two compositions are explained and compared with both the CeO2 structure and the Gd2O3 structure, i.e. the end member.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0021889803010288/ko5000sup1.cif
Contains datablocks global, I, II

rtv

Rietveld powder data file (CIF format) https://doi.org/10.1107/S0021889803010288/ko5000Isup2.rtv
Rietveld powder data file (CIF format) for Gd0.6Ce0.4O1.7

rtv

Rietveld powder data file (CIF format) https://doi.org/10.1107/S0021889803010288/ko5000IIsup3.rtv
Rietveld powder data file (CIF format) for Gd0.8Ce0.2O1.6

pdf

Portable Document Format (PDF) file https://doi.org/10.1107/S0021889803010288/ko5000sup4.pdf
Rietveld plots for Gd0.6Ce0.4O1.7 and Gd0.8Ce0.2O1.6

txt

Text file https://doi.org/10.1107/S0021889803010288/ko5000Isup5.txt
Profile file for Gd0.6Ce0.4O1.7

txt

Text file https://doi.org/10.1107/S0021889803010288/ko5000IIsup6.txt
Profile file for Gd0.8Ce0.2O1.6

Computing details top

For both compounds, program(s) used to refine structure: FULLPROF.

Figures top
[Figure 1]
[Figure 2]
[Figure 3]
(I) Gadolinium Cerium oxide top
Crystal data top
Gd0.6Ce0.4O1.70Dx = 7.38 Mg m3
Mr = 177.60X-ray radiation, λ = ? Å
Cubic, IA3T = 293 K
Hall symbol: -I 2b 2c 3White
a = 10.8542 (1) Åflat sheet, ? × ? × ? mm
V = 1278.76 (1) Å3Specimen preparation: Prepared at 1673K K, cooled at 2K/min K min1
Z = 32
Data collection top
Philips PW1710
diffractometer
Data collection mode: reflection
Radiation source: sealed X-ray tubeScan method: Step
Graphite 002 face monochromator2θmin = 10.000°, 2θmax = 110.000°, 2θstep = 0.020°
Specimen mounting: Sample pasted with on glass slide with collodion binder
Refinement top
Rp = 8.30Profile function: 'Pseudo-voigt function' 'U = 0.01502(471) V = -0.00722(529) W = 0.01885(145)' 'Eta = 0.633(35), X = 0.0069(8)'
Rwp = 11.41 parameters
Rexp = 9.250 restraints
RBragg = 4.79
χ2 = NOT FOUNDBackground function: 5th order polynomial function
5001 data pointsPreferred orientation correction: 'March function' axis (001), G1 = 0.9608(57),
Crystal data top
Gd0.6Ce0.4O1.70Z = 32
Mr = 177.60X-ray radiation, λ = ? Å
Cubic, IA3T = 293 K
a = 10.8542 (1) Åflat sheet, ? × ? × ? mm
V = 1278.76 (1) Å3
Data collection top
Philips PW1710
diffractometer
Scan method: Step
Specimen mounting: Sample pasted with on glass slide with collodion binder2θmin = 10.000°, 2θmax = 110.000°, 2θstep = 0.020°
Data collection mode: reflection
Refinement top
Rp = 8.30χ2 = NOT FOUND
Rwp = 11.45001 data points
Rexp = 9.251 parameters
RBragg = 4.790 restraints
Special details top

Experimental. Samples were prepared by solid state reaction of appropriate amounts of Gd2O3 and CeO2 at 1573 K followed by 1673 K for 48 hrs. Heating and cooling rates are 2 degrees per min. Details are given in manuscript

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/UeqOcc. (<1)
Gd10.250000.250000.250000.02984*0.6
Ce10.250000.250000.250000.02984*0.4
Gd20.0188 (2)0.000000.250000.01591*0.6
Ce20.0188 (2)0.000000.250000.01591*0.4
O10.3880 (17)0.1391 (16)0.376 (3)0.01635*0.95 (4)
O20.402 (2)0.402 (2)0.402 (2)0.01635*0.56 (4)
(II) Gadolinium Cerium oxide top
Crystal data top
Gd0.8Ce0.2O1.60Dx = 7.46 Mg m3
Mr = 179.40X-ray radiation, λ = 1.540600 Å
Cubic, IA3T = 293 K
Hall symbol: -I 2b 2c 3White
a = 10.8488 (1) Åflat sheet, ? × ? × ? mm
V = 1276.86 (2) Å3Specimen preparation: Prepared at 1673K K, cooled at 2K/min K min1
Z = 32
Data collection top
Philips PW1710
diffractometer
Data collection mode: reflection
Radiation source: sealed X-ray tubeScan method: Step
Graphite 002 face monochromator2θmin = 10.000°, 2θmax = 110.000°, 2θstep = 0.020°
Specimen mounting: Sample pasted with on glass slide with collodion binder'
Refinement top
Rp = 8.48Profile function: 'Pseudo-voigt function' 'U = 0.04722(448) , V = -0.04828(503), W = 0.02867(138)' 'Eta = 0.525(32), X = 0.0051(7)'
Rwp = 11.523 parameters
Rexp = 9.630 restraints
RBragg = 5.85
χ2 = NOT FOUNDBackground function: 5th order polynomial function
5001 data pointsPreferred orientation correction: 'March function' axis (001), G1 = 1.0088(61),
Crystal data top
Gd0.8Ce0.2O1.60Z = 32
Mr = 179.40X-ray radiation, λ = 1.540600 Å
Cubic, IA3T = 293 K
a = 10.8488 (1) Åflat sheet, ? × ? × ? mm
V = 1276.86 (2) Å3
Data collection top
Philips PW1710
diffractometer
Scan method: Step
Specimen mounting: Sample pasted with on glass slide with collodion binder'2θmin = 10.000°, 2θmax = 110.000°, 2θstep = 0.020°
Data collection mode: reflection
Refinement top
Rp = 8.48χ2 = NOT FOUND
Rwp = 11.55001 data points
Rexp = 9.6323 parameters
RBragg = 5.850 restraints
Special details top

Experimental. Samples were prepared by solid state reaction of appropriate amounts of Gd2O3 and CeO2 at 1573 K followed by 1673 K for 48 hrs. Heating and cooling rates are 2 degrees per min. Details are given in manuscript

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/UeqOcc. (<1)
Gd10.250000.250000.250000.00798*0.8
Gd10.250000.250000.250000.00798*0.2
Gd20.02515 (14)0.000000.250000.00391*0.8
Gd20.02515 (14)0.000000.250000.00391*0.2
O10.3911 (15)0.1470 (14)0.3763 (19)0.00636*0.96 (6)
O20.407 (3)0.407 (3)0.407 (3)0.00636*0.37 (6)

Experimental details

(I)(II)
Crystal data
Chemical formulaGd0.6Ce0.4O1.70Gd0.8Ce0.2O1.60
Mr177.60179.40
Crystal system, space groupCubic, IA3Cubic, IA3
Temperature (K)293293
a (Å)10.8542 (1) 10.8488 (1)
V3)1278.76 (1)1276.86 (2)
Z3232
Radiation typeX-ray, λ = ? ÅX-ray, λ = 1.540600 Å
Specimen shape, size (mm)Flat sheet, ? × ? × ?Flat sheet, ? × ? × ?
Data collection
DiffractometerPhilips PW1710
diffractometer
Philips PW1710
diffractometer
Specimen mountingSample pasted with on glass slide with collodion binderSample pasted with on glass slide with collodion binder'
Data collection modeReflectionReflection
Scan methodStepStep
2θ values (°)2θmin = 10.000 2θmax = 110.000 2θstep = 0.0202θmin = 10.000 2θmax = 110.000 2θstep = 0.020
Refinement
R factors and goodness of fitRp = 8.30, Rwp = 11.4, Rexp = 9.25, RBragg = 4.79, χ2 = NOT FOUNDRp = 8.48, Rwp = 11.5, Rexp = 9.63, RBragg = 5.85, χ2 = NOT FOUND
No. of data points50015001
No. of parameters123

Computer programs: FULLPROF.

 

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