Synchrotron radiation study of yttria-stabilized zirconia, Zr_0.758Y_0.242O_1.879

The fluorite-related cubic structure of yttria-stabilized zirconia, Zr_0.758Y_0.242O_1.879, has been studied by single-crystal X-ray diffraction using synchrotron radiation and by EXAFS. Two diffraction data sets obtained at X-ray energies of 512 and 10 eV below the Y K edge revealed that in the average structure Zr atoms are displaced from the origin of the space group Fm3m along <111> by 0.19 Å, while Y atoms reside at the origin. Approximately 48% of the O atoms occupy the ideal position in the fluorite-type structure, while 43% of O atoms are displaced from the ideal position along <001> by 0.31 Å. The remaining 9% of O atoms are presumably sited at interstitial positions. Local structures around Zr and Y are investigated by combining the results of single-crystal X-ray diffraction and EXAFS studies.

Computing details

For both compounds, data reduction: xtal_DIFDAT_ABSORB_SORTRF_ADDREF (Hall et al., 1995); program(s) used to solve structure: Xtal (Hall et al., 1995); program(s) used to refine structure: xtal_CRYLSQ (Hall et al., 1995); molecular graphics: Xtal (Hall et al., 1995). Software used to prepare material for publication: xtal_BONDLA_CIFIO (Hall et al., 1995) for ysz_f; xtal_CIFIO (Hall et al., 1995) for ysz_n.

Figures

(ysz_f) Yttrium Zirconium Oxide

Crystal data

Zr.758Y.242O1.879	F(000) = 219.16
Mr = 120.73	Dx = 5.855 Mg m^−3
Cubic, Fm3m	Synchrotron radiations radiation, λ = 0.7502 Å
Hall symbol: -F 4 2 3	µ = 7.71 mm^−1
a = 5.15463 (5) Å	T = 293 K
V = 136.96 (1) Å^3	, transparent colourless
Z = 4	0.02 (1) mm (radius)

Data collection

Horizontal-type four-circle diffractometer	Rint = 0.018
Si(111) double crystal monochromator	θmax = 68.7°, θmin = 7.2°
continuous θ/2θ scan	h = −12→12
Absorption correction: for a sphere ?	k = −12→12
Tmin = 0.818, Tmax = 0.823	l = −12→12
2277 measured reflections	6 standard reflections every 100 reflections
83 independent reflections	intensity decay: none
83 reflections with refl observed if F > 3.000 σ(F )

Refinement

Refinement on F	0 constraints
Least-squares matrix: full	σ
R[F^2 > 2σ(F^2)] = 0.005
wR(F^2) = 0.009	Δρmax = 0.28 e Å^−3
S = 6.18	Δρmin = −0.34 e Å^−3
83 reflections	Extinction correction: Becker & Coppens (1974a,b)
10 parameters	Extinction coefficient: 1972 (522)
0 restraints

Special details

Refinement. Sfls F σ weight full matrix

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Zr	0.02103 (9)	0.02103 (9)	0.02103 (9)	0.00862 (17)*
Y	0.00000	0.00000	0.00000	0.00591 (12)*
O1	0.25000	0.25000	0.25000	0.016 (2)*
O2	0.311 (5)	0.25000	0.25000	0.0144 (10)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
?	?	?	?	?	?	?

Bond lengths (Å)

Zr—O1	2.0442 (5)	Zr—O2^vi	2.126 (13)
Zr—O2	2.240 (16)	Zr—O2^vii	2.158 (10)
Zr—O1^i	2.3014 (5)	Zr—O2^viii	1.881 (11)
Zr—O2^i	2.477 (15)	Zr—O2^ix	2.254 (12)
Zr—O2^ii	2.504 (17)	Zr—O2^x	1.990 (13)
Zr—O1^iii	2.1766 (5)	Zr—O2^xi	2.024 (11)
Zr—O2^iii	2.361 (16)	Y—O1	2.2320 (1)
Zr—O2^iv	2.390 (18)	Y—O2	2.426 (16)
Zr—O1^v	2.4198 (5)	Y—O2^viii	2.067 (12)
Zr—O2^v	2.613 (16)

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

(ysz_n) Yttrium Zirconium Oxide

Crystal data

Zr.758Y.242O1.879	Dx = 5.855 Mg m^−3
Mr = 120.73	Synchrotron radiation radiation, λ = 0.7281 Å
Cubic, Fm3m	Cell parameters from 25 reflections
Hall symbol: -F 4 2 3	θ = 34.4–43.8°
a = 5.15463 (5) Å	µ = 7.12 mm^−1
V = 136.96 (1) Å^3	T = 293 K
Z = 4	, transparent colourless
F(000) = 219.16	0.02 (1) mm (radius)

Data collection

Horizontal-type four-circle diffractometer	Rint = 0.018
Si(111) double crystal monochromator	θmax = 69.8°, θmin = 7.0°
continuous θ/2θ scan	h = −13→13
Absorption correction: for a sphere ?	k = −13→13
Tmin = 0.831, Tmax = 0.835	l = −8→12
1258 measured reflections	6 standard reflections every 100 reflections
90 independent reflections	intensity decay: none
90 reflections with refl observed if F > 3.000 σ(F )

Refinement

Refinement on F	0 constraints
Least-squares matrix: full	σ
R[F^2 > 2σ(F^2)] = 0.009	(Δ/σ)max < 0.001
wR(F^2) = 0.013	Δρmax = 0.29 e Å^−3
S = 5.88	Δρmin = −0.46 e Å^−3
90 reflections	Extinction correction: Becker & Coppens (1974a,b)
10 parameters	Extinction coefficient: 1977 (215)
0 restraints

Special details

Refinement. Sfls F σ weight full matrix

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Y	0.00000	0.00000	0.00000	0.00056 (16)*
Zr	0.02186 (12)	0.02186 (12)	0.02186 (12)	0.0100 (2)*
O1	0.25000	0.25000	0.25000	0.019 (2)*
O2	0.317 (6)	0.25000	0.25000	0.014 (2)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
?	?	?	?	?	?	?