Triclinic and monoclinic structures of SrLaCuNbO6 and SrLaCuTaO6 double perovskites

West, D.V.; Davies, P.K.

doi:10.1107/S0021889811012131

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Triclinic and monoclinic structures of SrLaCuNbO₆ and SrLaCuTaO₆ double perovskites

D. V. West and P. K. Davies

SrLaCuNbO₆ and SrLaCuTaO₆ are Jahn-Teller distorted double perovskites with complete B-site ordering. The crystal structure of SrLaCuTaO₆ has been solved by refinement of neutron powder diffraction data at 323 (triclinic), 573 (monoclinic) and 923 K (body-centered monoclinic). Synchrotron X-ray and electron diffraction reveal local-scale features similar to those seen in ferroelectric perovskites, and also in A-site ordered perovskites exhibiting nanoscale periodicities. The crystal structure of SrLaCuNbO₆ was solved by refinement of synchrotron X-ray powder diffraction data at 673 and 1273 K. Because of the high resolution of the synchrotron, adjustments to these structure models were necessary in order to account for profile irregularities resulting from the local-scale behavior.

Keywords: triclinic structures; synchrotron radiation; X-ray diffraction; neutron diffraction; copper compounds; Jahn-Teller distortion; twinning; profile analysis.

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Supporting information

	Crystallographic Information File (CIF) https://doi.org/10.1107/S0021889811012131/he5515sup1.cif Contains datablocks global, SRLACUTAO6_NEUTRONS_323K_publ
	Crystallographic Information File (CIF) https://doi.org/10.1107/S0021889811012131/he5515sup2.cif Contains datablocks global, SRLACUTAO6_NEUTRONS_573K_publ
	Crystallographic Information File (CIF) https://doi.org/10.1107/S0021889811012131/he5515sup3.cif Contains datablocks global, SRLACUTAO6_NEUTRONS_923K_publ
	Crystallographic Information File (CIF) https://doi.org/10.1107/S0021889811012131/he5515sup4.cif Contains datablocks 380C_publ, 380C_overall, 380C_phase_1, 380C_phase_2, 380C_p_01
	Crystallographic Information File (CIF) https://doi.org/10.1107/S0021889811012131/he5515sup5.cif Contains datablocks SRLACUTAO6_XRAYS_1073K_2PHASE_publ, SRLACUTAO6_XRAYS_1073K_2PHASE_overall, SRLACUTAO6_XRAYS_1073K_2PHASE_phase_1, SRLACUTAO6_XRAYS_1073K_2PHASE_2, SRLACUTAO6_XRAYS_1073K_2PHASE_p_01
	Crystallographic Information File (CIF) https://doi.org/10.1107/S0021889811012131/he5515sup6.cif Contains datablocks SRLACUNBO6_XRAYS_673K_publ, SRLACUNBO6_XRAYS_673K_overall, SRLACUNBO6_XRAYS_673K_phase_1, SRLACUNBO6_XRAYS_673K_phase_2, SRLACUNBO6_XRAYS_673K_LaNbO4, SRLACUNBO6_XRAYS_673K_p_01
	Crystallographic Information File (CIF) https://doi.org/10.1107/S0021889811012131/he5515sup7.cif Contains datablocks SRLACUNBO6_XRAYS_1273K_publ, SRLACUNBO6_XRAYS_1273K_overall, SRLACUNBO6_XRAYS_1273K_phase_1, SRLACUNBO6_XRAYS_1273K_quartz, SRLACUNBO6_XRAYS_1273K_LaNbO4, SRLACUNBO6_XRAYS_1273K_p_01

Experimental top

(type here to add preparation details)

Computing details top

Program(s) used to refine structure: GSAS.

(SRLACUTAO6_NEUTRONS_323K_publ) top

Crystal data top

CuLaO₆SrTa	β = 90.319 (3)°
M_r = 567.01	γ = 90.090 (3)°
Triclinic, P1	V = 511.91 (3) Å³
Hall symbol: -P 1	Z = 4
a = 7.8015 (3) Å	Neutron radiation, λ = 1.5403 Å
b = 7.8126 (3) Å	T = 323 K
c = 8.3991 (3) Å	light yellow
α = 89.670 (3)°	?, ? × ? × ? mm

Data collection top

BT-1 diffractometer	Data collection mode: transmission
Radiation source: nuclear reactor	Scan method: step
Cu 311 monochromator	2θ_min = 3.034°, 2θ_max = 165.134°, 2θ_step = 0.05°

Refinement top

Refinement on I_net	Excluded region(s): 3 to 5 degrees no hkls and high background from instrument, 153 to 163 high background from instrument
Least-squares matrix: full	Profile function: CW Profile function number 1 with 6 terms Profile coefficients for Simpson's rule integration of Gaussian function C.J. Howard (1982). J. Appl. Cryst.,15,615-620. Cooper & Sayer, J. Appl. Cryst., 8, 615-618 (1975). Thomas, J. Appl. Cryst., 10, 12-13(1977). #1(U) = 406.192 #2(V) = -251.562 #3(W) = 170.373 #4(asym) = 5.0000 #5(F1) = 0.000 #6(F2) = 0.000 Peak tails are ignored where the intensity is below 0.0050 times the peak Aniso. broadening axis 0.0 0.0 1.0
R_p = 0.046	84 parameters
R_wp = 0.057	0 restraints
R_exp = 0.050	16 constraints
R(F²) = 0.04574	(Δ/σ)_max = 2.86
χ² = 1.369	Background function: GSAS Background function number 2 with 12 terms. Cosine Fourier series 1: 208.603 2: -13.9323 3: -10.3940 4: 32.2299 5: -37.0019 6: 32.7702 7: -24.8469 8: 24.6023 9: -14.5494 10: 15.6911 11: -8.29850 12: -1.10809
3243 data points

Crystal data top

CuLaO₆SrTa	β = 90.319 (3)°
M_r = 567.01	γ = 90.090 (3)°
Triclinic, P1	V = 511.91 (3) Å³
a = 7.8015 (3) Å	Z = 4
b = 7.8126 (3) Å	Neutron radiation, λ = 1.5403 Å
c = 8.3991 (3) Å	T = 323 K
α = 89.670 (3)°	?, ? × ? × ? mm

Data collection top

BT-1 diffractometer	Scan method: step
Data collection mode: transmission	2θ_min = 3.034°, 2θ_max = 165.134°, 2θ_step = 0.05°

Refinement top

R_p = 0.046	3243 data points
R_wp = 0.057	84 parameters
R_exp = 0.050	0 restraints
R(F²) = 0.04574	(Δ/σ)_max = 2.86
χ² = 1.369

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

	x	y	z	U_iso*/U_eq	Occ. (<1)
Ta1	−0.001 (3)	0.245 (3)	0.2439 (19)	0.0089 (12)*
Ta2	0.499 (3)	0.254 (3)	0.747 (2)	0.0089 (12)*
Cu1	−0.001 (2)	0.246 (2)	0.7414 (19)	0.0086 (10)*
Cu2	0.497 (3)	0.252 (3)	0.253 (2)	0.0086 (10)*
La1	0.252 (2)	0.488 (3)	0.4939 (18)	0.0154 (7)*	0.5
Sr1	0.252 (2)	0.488 (3)	0.4939 (18)	0.0154 (7)*	0.5
La2	0.247 (2)	−0.019 (2)	0.4927 (17)	0.0154 (7)*	0.5
Sr2	0.247 (2)	−0.019 (2)	0.4927 (17)	0.0154 (7)*	0.5
La3	0.255 (2)	0.487 (2)	−0.0222 (15)	0.0154 (7)*	0.5
Sr3	0.255 (2)	0.487 (2)	−0.0222 (15)	0.0154 (7)*	0.5
La4	0.753 (2)	0.017 (3)	0.0144 (19)	0.0154 (7)*	0.5
Sr4	0.753 (2)	0.017 (3)	0.0144 (19)	0.0154 (7)*	0.5
O11	0.041 (3)	−0.006 (3)	0.219 (2)	0.0145 (4)*
O12	−0.047 (2)	0.286 (3)	0.026 (2)	0.0145 (4)*
O13	−0.034 (3)	0.504 (3)	0.295 (2)	0.0145 (4)*
O14	0.031 (2)	0.219 (3)	0.484 (2)	0.0145 (4)*
O21	0.252 (3)	0.286 (3)	0.224 (2)	0.0145 (4)*
O22	0.250 (3)	0.231 (2)	0.7838 (17)	0.0145 (4)*
O23	0.254 (3)	0.723 (2)	0.3081 (18)	0.0145 (4)*
O24	0.244 (3)	0.787 (3)	0.716 (2)	0.0145 (4)*
O31	0.455 (2)	0.001 (2)	0.229 (2)	0.0145 (4)*
O32	0.539 (3)	0.279 (3)	−0.021 (2)	0.0145 (4)*
O33	0.458 (3)	0.210 (3)	0.519 (2)	0.0145 (4)*
O34	0.517 (2)	0.496 (3)	0.289 (2)	0.0145 (4)*

Bond lengths (Å) top

Ta1—La1	3.45 (3)	La3—Sr1^xiii	4.064 (18)
Ta1—La1ⁱ	3.63 (2)	La3—Sr1	4.335 (18)
Ta1—Sr1	3.45 (3)	La3—La3ⁱⁱⁱ	4.01 (3)
Ta1—Sr1ⁱ	3.63 (2)	La3—La3^x	3.84 (3)
Ta1—La2	3.50 (3)	La3—Sr3ⁱⁱⁱ	4.01 (3)
Ta1—La2ⁱⁱ	3.42 (2)	La3—Sr3^x	3.84 (3)
Ta1—Sr2	3.50 (3)	La3—La4^v	3.94 (3)
Ta1—Sr2ⁱⁱ	3.42 (2)	La3—La4^x	3.88 (3)
Ta1—La3	3.54 (3)	La3—Sr4^v	3.94 (3)
Ta1—La3ⁱⁱⁱ	3.43 (3)	La3—Sr4^x	3.88 (3)
Ta1—Sr3	3.54 (3)	La3—O12	2.86 (3)
Ta1—Sr3ⁱⁱⁱ	3.43 (3)	La3—O12ⁱⁱⁱ	2.41 (2)
Ta1—La4^iv	3.25 (3)	La3—O13ⁱⁱⁱ	2.86 (3)
Ta1—La4^v	3.57 (2)	La3—O21	2.59 (3)
Ta1—Sr4^iv	3.25 (3)	La3—O22^xiii	2.59 (3)
Ta1—Sr4^v	3.57 (2)	La3—O32	2.75 (3)
Ta1—O11	2.00 (3)	La3—O32^x	2.46 (3)
Ta1—O12	1.89 (3)	La3—O34^x	2.87 (2)
Ta1—O13	2.10 (3)	Sr3—Ta1	3.54 (3)
Ta1—O14	2.04 (3)	Sr3—Ta1ⁱⁱⁱ	3.43 (3)
Ta1—O21	2.01 (3)	Sr3—Ta2^xiii	3.28 (3)
Ta1—O24ⁱ	1.94 (3)	Sr3—Ta2^vi	3.62 (2)
Ta2—La1	3.39 (3)	Sr3—Cu1^xiii	3.39 (2)
Ta2—La1^vi	3.45 (3)	Sr3—Cu1ⁱ	3.741 (19)
Ta2—Sr1	3.39 (3)	Sr3—Cu2	3.49 (2)
Ta2—Sr1^vi	3.45 (3)	Sr3—Cu2^x	3.42 (3)
Ta2—La2	3.60 (2)	Sr3—La1^xiii	4.064 (18)
Ta2—La2^vii	3.39 (3)	Sr3—La1	4.335 (18)
Ta2—Sr2	3.60 (2)	Sr3—Sr1^xiii	4.064 (18)
Ta2—Sr2^vii	3.39 (3)	Sr3—Sr1	4.335 (18)
Ta2—La3^viii	3.28 (3)	Sr3—La3ⁱⁱⁱ	4.01 (3)
Ta2—La3^vi	3.62 (2)	Sr3—La3^x	3.84 (3)
Ta2—Sr3^viii	3.28 (3)	Sr3—Sr3ⁱⁱⁱ	4.01 (3)
Ta2—Sr3^vi	3.62 (2)	Sr3—Sr3^x	3.84 (3)
Ta2—La4^viii	3.51 (3)	Sr3—La4^v	3.94 (3)
Ta2—La4^vii	3.52 (3)	Sr3—La4^x	3.88 (3)
Ta2—Sr4^viii	3.51 (3)	Sr3—Sr4^v	3.94 (3)
Ta2—Sr4^vii	3.52 (3)	Sr3—Sr4^x	3.88 (3)
Ta2—O22	1.98 (3)	Sr3—O12	2.86 (3)
Ta2—O23^vi	2.00 (3)	Sr3—O12ⁱⁱⁱ	2.41 (2)
Ta2—O31^vii	2.04 (3)	Sr3—O13ⁱⁱⁱ	2.86 (3)
Ta2—O32^viii	1.98 (2)	Sr3—O21	2.59 (3)
Ta2—O33	1.97 (2)	Sr3—O22^xiii	2.59 (3)
Ta2—O34^vi	1.97 (3)	Sr3—O23	3.342 (18)
Cu1—La1	3.43 (3)	Sr3—O24^xiii	3.21 (3)
Cu1—La1ⁱ	3.46 (3)	Sr3—O32	2.75 (3)
Cu1—Sr1	3.43 (3)	Sr3—O32^x	2.46 (3)
Cu1—Sr1ⁱ	3.46 (3)	Sr3—O34	3.31 (3)
Cu1—La2	3.53 (2)	Sr3—O34^x	2.87 (2)
Cu1—La2ⁱⁱ	3.27 (2)	La4—Ta1^xiv	3.25 (3)
Cu1—Sr2	3.53 (2)	La4—Ta1^v	3.57 (2)
Cu1—Sr2ⁱⁱ	3.27 (2)	La4—Ta2^xiii	3.51 (3)
Cu1—La3^viii	3.39 (2)	La4—Ta2^vii	3.52 (3)
Cu1—Sr3^viii	3.39 (2)	La4—Cu1^xv	3.48 (3)
Cu1—Sr3ⁱ	3.741 (19)	La4—Cu1^vii	3.48 (3)
Cu1—La4^ix	3.48 (3)	La4—Cu2	3.39 (2)
Cu1—La4^vii	3.48 (3)	La4—La2^vii	4.14 (2)
Cu1—Sr4^ix	3.48 (3)	La4—Sr2^v	4.26 (2)
Cu1—Sr4^vii	3.48 (3)	La4—Sr2^vii	4.14 (2)
Cu1—O11ⁱⁱ	1.93 (3)	La4—La3^v	3.94 (3)
Cu1—O12^viii	2.44 (2)	La4—La3^x	3.88 (3)
Cu1—O13ⁱ	1.99 (3)	La4—Sr3^v	3.94 (3)
Cu1—O14	2.19 (2)	La4—Sr3^x	3.88 (3)
Cu1—O22	1.99 (3)	La4—La4^v	3.96 (4)
Cu1—O23ⁱ	2.03 (3)	La4—La4^xvi	3.87 (3)
Cu2—La1	3.36 (2)	La4—Sr4^v	3.96 (4)
Cu2—La1^vi	3.53 (2)	La4—Sr4^xvi	3.87 (3)
Cu2—Sr1	3.36 (2)	La4—O11^xiv	2.83 (3)
Cu2—Sr1^vi	3.53 (2)	La4—O11^v	2.54 (3)
Cu2—La2	3.50 (3)	La4—O12^xiv	2.62 (3)
Cu2—La2^vii	3.43 (3)	La4—O21^v	3.12 (3)
Cu2—Sr2	3.50 (3)	La4—O22^vii	2.57 (2)
Cu2—Sr2^vii	3.43 (3)	La4—O24^vi	2.74 (3)
Cu2—La3	3.49 (2)	La4—O31	2.95 (2)
Cu2—La3^x	3.42 (3)	La4—O31^v	2.60 (3)
Cu2—Sr3	3.49 (2)	La4—O32	2.65 (3)
Cu2—Sr3^x	3.42 (3)	Sr4—Ta1^xiv	3.25 (3)
Cu2—La4	3.39 (2)	Sr4—Ta1^v	3.57 (2)
Cu2—Sr4	3.39 (2)	Sr4—Ta2^xiii	3.51 (3)
Cu2—Sr4^v	3.64 (3)	Sr4—Ta2^vii	3.52 (3)
Cu2—O21	1.95 (3)	Sr4—Cu1^xv	3.48 (3)
Cu2—O24^vi	2.06 (3)	Sr4—Cu1^vii	3.48 (3)
Cu2—O31	2.00 (3)	Sr4—Cu2	3.39 (2)
Cu2—O32	2.34 (2)	Sr4—Cu2^v	3.64 (3)
Cu2—O33	2.28 (2)	Sr4—La2^v	4.26 (2)
Cu2—O34	1.94 (3)	Sr4—La2^vii	4.14 (2)
La1—Ta1	3.45 (3)	Sr4—Sr2^v	4.26 (2)
La1—Ta1ⁱ	3.63 (2)	Sr4—Sr2^vii	4.14 (2)
La1—Ta2	3.39 (3)	Sr4—La3^v	3.94 (3)
La1—Ta2^vi	3.45 (3)	Sr4—La3^x	3.88 (3)
La1—Cu1	3.43 (3)	Sr4—Sr3^v	3.94 (3)
La1—Cu1ⁱ	3.46 (3)	Sr4—Sr3^x	3.88 (3)
La1—Cu2	3.36 (2)	Sr4—La4^v	3.96 (4)
La1—Cu2^vi	3.53 (2)	Sr4—La4^xvi	3.87 (3)
La1—La1ⁱ	3.93 (4)	Sr4—Sr4^v	3.96 (4)
La1—La1^vi	3.88 (4)	Sr4—Sr4^xvi	3.87 (3)
La1—Sr1ⁱ	3.93 (4)	Sr4—O11^xiv	2.83 (3)
La1—Sr1^vi	3.88 (4)	Sr4—O11^v	2.54 (3)
La1—La2	3.96 (3)	Sr4—O12^xiv	2.62 (3)
La1—La2^xi	3.85 (3)	Sr4—O12^v	3.32 (2)
La1—Sr2	3.96 (3)	Sr4—O21^v	3.12 (3)
La1—Sr2^xi	3.85 (3)	Sr4—O22^vii	2.57 (2)
La1—La3^viii	4.064 (18)	Sr4—O23^x	3.37 (3)
La1—Sr3	4.335 (18)	Sr4—O24^vi	2.74 (3)
La1—Sr3^viii	4.064 (18)	Sr4—O31	2.95 (2)
La1—O13	2.78 (3)	Sr4—O31^v	2.60 (3)
La1—O13ⁱ	2.46 (3)	Sr4—O32	2.65 (3)
La1—O14	2.72 (3)	Sr4—O32^v	3.24 (3)
La1—O21	2.77 (3)	O11—Ta1	2.00 (3)
La1—O22	3.15 (3)	O11—Cu1ⁱⁱ	1.93 (3)
La1—O23	2.40 (3)	O11—La2	2.80 (3)
La1—O24	3.00 (3)	O11—Sr2	2.80 (3)
La1—O33	2.72 (3)	O11—Sr2ⁱⁱ	3.32 (2)
La1—O34	2.70 (2)	O11—La4^iv	2.83 (3)
La1—O34^vi	2.56 (3)	O11—La4^v	2.54 (3)
Sr1—Ta1	3.45 (3)	O11—Sr4^iv	2.83 (3)
Sr1—Ta1ⁱ	3.63 (2)	O11—Sr4^v	2.54 (3)
Sr1—Ta2	3.39 (3)	O12—Ta1	1.89 (3)
Sr1—Ta2^vi	3.45 (3)	O12—Cu1^xiii	2.44 (2)
Sr1—Cu1	3.43 (3)	O12—La3	2.86 (3)
Sr1—Cu1ⁱ	3.46 (3)	O12—La3ⁱⁱⁱ	2.41 (2)
Sr1—Cu2	3.36 (2)	O12—Sr3	2.86 (3)
Sr1—Cu2^vi	3.53 (2)	O12—Sr3ⁱⁱⁱ	2.41 (2)
Sr1—La1ⁱ	3.93 (4)	O12—La4^iv	2.62 (3)
Sr1—La1^vi	3.88 (4)	O12—Sr4^iv	2.62 (3)
Sr1—Sr1ⁱ	3.93 (4)	O12—Sr4^v	3.32 (2)
Sr1—Sr1^vi	3.88 (4)	O13—Ta1	2.10 (3)
Sr1—La2	3.96 (3)	O13—Cu1ⁱ	1.99 (3)
Sr1—La2^xi	3.85 (3)	O13—La1	2.78 (3)
Sr1—Sr2	3.96 (3)	O13—La1ⁱ	2.46 (3)
Sr1—Sr2^xi	3.85 (3)	O13—Sr1	2.78 (3)
Sr1—La3	4.335 (18)	O13—Sr1ⁱ	2.46 (3)
Sr1—La3^viii	4.064 (18)	O13—La3ⁱⁱⁱ	2.86 (3)
Sr1—Sr3	4.335 (18)	O13—Sr3ⁱⁱⁱ	2.86 (3)
Sr1—Sr3^viii	4.064 (18)	O14—Ta1	2.04 (3)
Sr1—O13	2.78 (3)	O14—Cu1	2.19 (2)
Sr1—O13ⁱ	2.46 (3)	O14—La1	2.72 (3)
Sr1—O14	2.72 (3)	O14—Sr1	2.72 (3)
Sr1—O14ⁱ	3.18 (3)	O14—Sr1ⁱ	3.18 (3)
Sr1—O21	2.77 (3)	O14—La2	2.51 (3)
Sr1—O22	3.15 (3)	O14—La2ⁱⁱ	2.68 (3)
Sr1—O23	2.40 (3)	O14—Sr2	2.51 (3)
Sr1—O24	3.00 (3)	O14—Sr2ⁱⁱ	2.68 (3)
Sr1—O33	2.72 (3)	O21—Ta1	2.01 (3)
Sr1—O33^vi	3.27 (3)	O21—Cu2	1.95 (3)
Sr1—O34	2.70 (2)	O21—La1	2.77 (3)
Sr1—O34^vi	2.56 (3)	O21—Sr1	2.77 (3)
La2—Ta1	3.50 (3)	O21—Sr2	3.27 (3)
La2—Ta1ⁱⁱ	3.42 (2)	O21—La3	2.59 (3)
La2—Ta2	3.60 (2)	O21—Sr3	2.59 (3)
La2—Ta2^vii	3.39 (3)	O21—La4^v	3.12 (3)
La2—Cu1	3.53 (2)	O21—Sr4^v	3.12 (3)
La2—Cu1ⁱⁱ	3.27 (2)	O22—Ta2	1.98 (3)
La2—Cu2	3.50 (3)	O22—Cu1	1.99 (3)
La2—Cu2^vii	3.43 (3)	O22—La1	3.15 (3)
La2—La1^xii	3.85 (3)	O22—Sr1	3.15 (3)
La2—La1	3.96 (3)	O22—La2	3.14 (2)
La2—Sr1^xii	3.85 (3)	O22—Sr2	3.14 (2)
La2—Sr1	3.96 (3)	O22—La3^viii	2.59 (3)
La2—La2ⁱⁱ	3.87 (4)	O22—Sr3^viii	2.59 (3)
La2—La2^vii	3.96 (4)	O22—La4^vii	2.57 (2)
La2—Sr2ⁱⁱ	3.87 (4)	O22—Sr4^vii	2.57 (2)
La2—Sr2^vii	3.96 (4)	O23—Ta2^vi	2.00 (3)
La2—La4^vii	4.14 (2)	O23—Cu1ⁱ	2.03 (3)
La2—Sr4^v	4.26 (2)	O23—La1	2.40 (3)
La2—Sr4^vii	4.14 (2)	O23—Sr1	2.40 (3)
La2—O11	2.80 (3)	O23—La2^xi	2.55 (3)
La2—O14	2.51 (3)	O23—Sr2^xi	2.55 (3)
La2—O14ⁱⁱ	2.68 (3)	O23—Sr3	3.342 (18)
La2—O22	3.14 (2)	O23—Sr4^x	3.37 (3)
La2—O23^xii	2.55 (3)	O24—Ta1ⁱ	1.94 (3)
La2—O24^xii	2.41 (2)	O24—Cu2^vi	2.06 (3)
La2—O31	2.76 (2)	O24—La1	3.00 (3)
La2—O33	2.44 (2)	O24—Sr1	3.00 (3)
La2—O33^vii	2.75 (3)	O24—La2^xi	2.41 (2)
Sr2—Ta1	3.50 (3)	O24—Sr2^xi	2.41 (2)
Sr2—Ta1ⁱⁱ	3.42 (2)	O24—Sr3^viii	3.21 (3)
Sr2—Ta2	3.60 (2)	O24—La4^vi	2.74 (3)
Sr2—Ta2^vii	3.39 (3)	O24—Sr4^vi	2.74 (3)
Sr2—Cu1	3.53 (2)	O31—Ta2^vii	2.04 (3)
Sr2—Cu1ⁱⁱ	3.27 (2)	O31—Cu2	2.00 (3)
Sr2—Cu2	3.50 (3)	O31—La2	2.76 (2)
Sr2—Cu2^vii	3.43 (3)	O31—Sr2	2.76 (2)
Sr2—La1^xii	3.85 (3)	O31—Sr2^vii	3.30 (3)
Sr2—La1	3.96 (3)	O31—La4	2.95 (2)
Sr2—Sr1^xii	3.85 (3)	O31—La4^v	2.60 (3)
Sr2—Sr1	3.96 (3)	O31—Sr4	2.95 (2)
Sr2—La2ⁱⁱ	3.87 (4)	O31—Sr4^v	2.60 (3)
Sr2—La2^vii	3.96 (4)	O32—Ta2^xiii	1.98 (2)
Sr2—Sr2ⁱⁱ	3.87 (4)	O32—Cu2	2.34 (2)
Sr2—Sr2^vii	3.96 (4)	O32—La3	2.75 (3)
Sr2—La4^v	4.26 (2)	O32—La3^x	2.46 (3)
Sr2—La4^vii	4.14 (2)	O32—Sr3	2.75 (3)
Sr2—Sr4^v	4.26 (2)	O32—Sr3^x	2.46 (3)
Sr2—Sr4^vii	4.14 (2)	O32—La4	2.65 (3)
Sr2—O11	2.80 (3)	O32—Sr4	2.65 (3)
Sr2—O11ⁱⁱ	3.32 (2)	O32—Sr4^v	3.24 (3)
Sr2—O14	2.51 (3)	O33—Ta2	1.97 (2)
Sr2—O14ⁱⁱ	2.68 (3)	O33—Cu2	2.28 (2)
Sr2—O21	3.27 (3)	O33—La1	2.72 (3)
Sr2—O22	3.14 (2)	O33—Sr1	2.72 (3)
Sr2—O23^xii	2.55 (3)	O33—Sr1^vi	3.27 (3)
Sr2—O24^xii	2.41 (2)	O33—La2	2.44 (2)
Sr2—O31	2.76 (2)	O33—La2^vii	2.75 (3)
Sr2—O31^vii	3.30 (3)	O33—Sr2	2.44 (2)
Sr2—O33	2.44 (2)	O33—Sr2^vii	2.75 (3)
Sr2—O33^vii	2.75 (3)	O34—Ta2^vi	1.97 (3)
La3—Ta1	3.54 (3)	O34—Cu2	1.94 (3)
La3—Ta1ⁱⁱⁱ	3.43 (3)	O34—La1	2.70 (2)
La3—Ta2^xiii	3.28 (3)	O34—La1^vi	2.56 (3)
La3—Ta2^vi	3.62 (2)	O34—Sr1	2.70 (2)
La3—Cu1^xiii	3.39 (2)	O34—Sr1^vi	2.56 (3)
La3—Cu2	3.49 (2)	O34—La3^x	2.87 (2)
La3—Cu2^x	3.42 (3)	O34—Sr3	3.31 (3)
La3—La1^xiii	4.064 (18)	O34—Sr3^x	2.87 (2)

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

Experimental details

Crystal data
Chemical formula	CuLaO₆SrTa
M_r	567.01
Crystal system, space group	Triclinic, P1
Temperature (K)	323
a, b, c (Å)	7.8015 (3), 7.8126 (3), 8.3991 (3)
α, β, γ (°)	89.670 (3), 90.319 (3), 90.090 (3)
V (Å³)	511.91 (3)
Z	4
Radiation type	Neutron, λ = 1.5403 Å
µ (mm⁻¹)	?
Specimen shape, size (mm)	?, ? × ? × ?

Data collection
Diffractometer	BT-1 diffractometer
Specimen mounting	?
Data collection mode	Transmission
Scan method	Step
Absorption correction	? GSAS Absorption/surface roughness correction: function number 0 No correction is applied.
T_min, T_max	1.000, 1.000
2θ values (°)	2θ_min = 3.034 2θ_max = 165.134 2θ_step = 0.05

Refinement
R factors and goodness of fit	R_p = 0.046, R_wp = 0.057, R_exp = 0.050, R(F²) = 0.04574, χ² = 1.369
No. of data points	3243
No. of parameters	84
(Δ/σ)_max	2.86

Computer programs: GSAS.

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