Solution and refinement of the crystal structure of Bi7Ta3O18

Ling, C.D.; Schmid, S.; Withers, R.L.; Thompson, J.G.; Ishizawa, N.; Kishimoto, S.

doi:10.1107/S0108768198011148

Solution and refinement of the crystal structure of Bi₇Ta₃O₁₈

C. D. Ling, S. Schmid, R. L. Withers, J. G. Thompson, N. Ishizawa and S. Kishimoto

The structure of heptabismuth tritantalum octadecaoxide, Bi₇Ta₃O₁₈, has been solved and refined using single-crystal X-ray diffraction data collected at a synchrotron source in conjunction with unit-cell and symmetry information derived from electron diffraction. The space-group symmetry is triclinic C1 but is very close to monoclinic C2/m. A twin component observed during data collection was successfully modelled in the refinement. The C2/m prototype fitted all the Rietveld-refinable features of a medium-resolution neutron powder diffraction pattern. The metal-atom array is approximately face-centred cubic (fluorite type), punctuated by regularly spaced displacement faults perpendicular to the [111]_fluorite direction every 2.5 fluorite unit cells. The metal-atom populations and O-atom positions are fully ordered. The Ta⁵⁺ cations are octahedrally coordinated, with TaO₆ octahedra forming columns. The remaining O atoms occupy distorted fluorite positions. The Bi³⁺ cations occupy octahedral, square pyramidal or trigonal prismatic sites within the O-atom array; strain in the latter coordination environment appears to be responsible for the lowering of symmetry from monoclinic to triclinic.

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Supporting information

	Crystallographic Information File (CIF) Contains datablocks xtl, global, pow
	Rietveld powder data file (CIF format) Contains datablock pow
	Structure factor file (SHELXL table format) Supplementary material

Computing details top

Data reduction: Xtal DIFDAT SORTRF ADDREF ABSORB for xtl. Program(s) used to solve structure: Xtal for xtl. Program(s) used to refine structure: Xtal LSLS for xtl; GSAS for pow. Molecular graphics: Xtal for xtl. Software used to prepare material for publication: Xtal CIFIO for xtl.

Figures top

(xtl) bismuth tantalum oxide top

Crystal data top

Bi₇O₁₈Ta₃	Z = 4
M_r = 2293.71	F(000) = 3776
Triclinic, C1	D_x = 9.4 Mg m⁻³
Hall symbol: C 1	Synchrotron radiation, λ = 0.9580 (4) Å
a = 34.005 (3) Å	Cell parameters from 25 reflections
b = 7.6024 (4) Å	θ = 22.8–38.0°
c = 6.6358 (5) Å	µ = 85.4 mm⁻¹
α = 90.086 (6)°	T = 293 K
β = 109.127 (6)°	Plate, yellow
γ = 90.043 (6)°	0.02 × 0.02 × 0.002 mm
V = 1620.8 (2) Å³

Data collection top

Tsukuba diffractometer	R_int = 0.023
Radiation source: synchrotron	θ_max = 50°, θ_min = 1.7°
Si monochromator	h = −54→54
Absorption correction: gaussian ?	k = −12→12
T_min = 0.277, T_max = 0.844	l = −10→10
0.176040+05 measured reflections	6 standard reflections every 200 reflections
0.137980+05 independent reflections	intensity decay: none
0.117960+05 reflections with refl observed if F² > 3.000 σ(F²)

Refinement top

Refinement on F²	1 constraint
Least-squares matrix: Full matrix	w = 1/σ²
R[F² > 2σ(F²)] = 0.039	(Δ/σ)_max = 0.001
wR(F²) = 0.0337	Δρ_max = 5.80 e Å⁻³
0.117960+05 reflections	Δρ_min = −5.61 e Å⁻³
327 parameters	Extinction correction: Zachariasen (1968), Eq22 p292 "Cryst. Comp." Munksgaard 1970
0 restraints	Extinction coefficient: 1828 (30)

Crystal data top

Bi₇O₁₈Ta₃	γ = 90.043 (6)°
M_r = 2293.71	V = 1620.8 (2) Å³
Triclinic, C1	Z = 4
a = 34.005 (3) Å	Synchrotron radiation, λ = 0.9580 (4) Å
b = 7.6024 (4) Å	µ = 85.4 mm⁻¹
c = 6.6358 (5) Å	T = 293 K
α = 90.086 (6)°	0.02 × 0.02 × 0.002 mm
β = 109.127 (6)°

Data collection top

Tsukuba diffractometer	0.117960+05 reflections with refl observed if F² > 3.000 σ(F²)
Absorption correction: gaussian ?	R_int = 0.023
T_min = 0.277, T_max = 0.844	6 standard reflections every 200 reflections
0.176040+05 measured reflections	intensity decay: none
0.137980+05 independent reflections

Refinement top

R[F² > 2σ(F²)] = 0.039	0 restraints
wR(F²) = 0.0337	Δρ_max = 5.80 e Å⁻³
0.117960+05 reflections	Δρ_min = −5.61 e Å⁻³
327 parameters

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

	x	y	z	U_iso*/U_eq
Bi1	0.34035 (3)	0.23954 (9)	0.48808 (13)	0.0175 (4)
Bi2	0.338481 (19)	−0.49941 (8)	−0.03295 (9)	0.0077 (3)
Bi3	0.352745 (18)	0.00191 (8)	0.00818 (8)	0.0078 (3)
Ta4	0.439500 (19)	0.25362 (8)	−0.02517 (10)	0.0053 (2)
Bi5	0.13920 (2)	0.25045 (8)	0.42381 (9)	0.0084 (3)
Ta6	0.44073 (2)	−0.24841 (8)	−0.01788 (10)	0.0052 (3)
Bi7	0.145987 (18)	−0.49905 (7)	−0.03491 (8)	0.0074 (3)
Ta8	0.25045 (2)	−0.25148 (9)	0.00335 (10)	0.0055 (2)
Bi9	0.13846 (2)	−0.25211 (8)	0.42799 (10)	0.0106 (3)
Bi10	0.35341 (2)	−0.25195 (9)	−0.49329 (11)	0.0149 (4)
Bi11	0.44582 (2)	0.01013 (9)	−0.47120 (9)	0.0108 (3)
Ta12	0.051995 (18)	−0.25145 (7)	−0.03194 (9)	0.0052 (3)
Bi13	0.249612 (19)	−0.00439 (8)	−0.47642 (9)	0.0076 (3)
Bi14	0.05081 (2)	0.00216 (9)	−0.50979 (10)	0.0095 (3)
Ta15	0.24956 (2)	0.25148 (9)	−0.00335 (11)	0.0059 (2)
Bi16	0.246719 (19)	−0.49654 (9)	0.46346 (9)	0.0090 (3)
Bi17	0.045577 (19)	−0.49984 (8)	0.42758 (9)	0.0097 (3)
Ta18	0.052326 (18)	0.25109 (7)	−0.03323 (9)	0.0049 (3)
Bi19	0.158172 (19)	−0.00140 (8)	−0.00700 (8)	0.0088 (3)
Bi20	0.44170 (2)	−0.50124 (8)	0.46484 (9)	0.0079 (3)
O1	0.4279 (3)	0.0028 (12)	−0.1082 (13)	0.0066 (14)*
O2	0.3787 (3)	−0.2898 (13)	−0.1112 (15)	0.0104 (16)*
O3	0.1165 (3)	−0.2130 (12)	0.0673 (14)	0.0084 (15)*
O4	0.3789 (3)	0.2971 (13)	−0.1083 (15)	0.0117 (17)*
O5	0.1162 (3)	0.2103 (11)	0.0686 (13)	0.0053 (14)*
O6	0.0674 (3)	0.2152 (12)	0.2988 (14)	0.0068 (15)*
O7	0.4455 (3)	0.2042 (13)	0.2681 (15)	0.0127 (17)*
O8	0.4476 (3)	−0.1953 (13)	0.2686 (16)	0.0137 (18)*
O9	0.4247 (3)	−0.2881 (12)	−0.3500 (14)	0.0096 (16)*
O10	0.4971 (3)	−0.2166 (12)	−0.0312 (14)	0.0087 (15)*
O11	0.2356 (3)	0.0006 (13)	−0.0646 (15)	0.0124 (16)*
O12	0.3814 (3)	−0.0066 (13)	0.4020 (14)	0.0095 (15)*
O13	0.2581 (3)	−0.2062 (13)	0.3109 (15)	0.0129 (17)*
O14	0.4506 (3)	−0.4968 (13)	0.0500 (15)	0.0119 (17)*
O15	0.2662 (3)	0.2029 (11)	0.3241 (13)	0.0085 (14)*
O16	0.1632 (3)	−0.4978 (13)	0.3090 (14)	0.0100 (15)*
O17	0.3246 (3)	0.0028 (14)	−0.3502 (15)	0.0146 (17)*
O18	0.0456 (3)	−0.0030 (13)	−0.1058 (14)	0.0110 (16)*
O19	0.3779 (3)	−0.4902 (14)	0.3089 (15)	0.0144 (17)*
O20	0.1917 (3)	0.2938 (12)	−0.0200 (14)	0.0117 (16)*
O21	0.1131 (3)	0.0024 (14)	−0.3657 (15)	0.0144 (17)*
O22	0.1907 (3)	−0.2977 (14)	−0.0463 (16)	0.0158 (18)*
O23	0.0671 (3)	−0.5002 (13)	0.0475 (13)	0.0083 (15)*
O24	0.1805 (3)	0.0085 (14)	0.3466 (16)	0.0142 (18)*
O25	0.1098 (3)	−0.4942 (14)	−0.4592 (16)	0.0136 (17)*
O26	0.0476 (3)	0.2990 (12)	−0.3211 (14)	0.0094 (16)*
O27	0.0687 (3)	−0.2092 (13)	0.2996 (15)	0.0106 (16)*
O28	0.2646 (3)	−0.4973 (12)	0.0867 (14)	0.0105 (15)*
O29	0.4278 (3)	0.2940 (13)	−0.3478 (15)	0.0107 (16)*
O30	0.0448 (3)	−0.2963 (14)	−0.3225 (16)	0.0148 (18)*
O31	0.3110 (3)	0.2065 (13)	0.0623 (15)	0.0151 (18)*
O32	0.3111 (3)	−0.1971 (14)	0.0691 (17)	0.019 (2)*
O33	0.2428 (3)	0.3012 (15)	−0.2909 (17)	0.022 (2)*
O34	0.3141 (3)	−0.5071 (14)	−0.4091 (16)	0.0153 (18)*
O35	0.2463 (3)	−0.3006 (14)	−0.2943 (17)	0.019 (2)*
O36	0.4982 (3)	0.2185 (13)	−0.0190 (14)	0.0095 (16)*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Bi1	0.0304 (4)	0.0088 (3)	0.0224 (3)	0.0040 (3)	0.0180 (3)	0.0028 (2)
Bi2	0.0076 (2)	0.0086 (2)	0.0075 (2)	−0.0001 (2)	0.00230 (19)	−0.0002 (2)
Bi3	0.0068 (2)	0.0082 (2)	0.0083 (2)	0.0004 (2)	0.00184 (18)	−0.0001 (2)
Ta4	0.0058 (2)	0.0051 (2)	0.0056 (2)	−0.00038 (16)	0.00254 (16)	−0.00041 (15)
Bi5	0.0111 (2)	0.0093 (2)	0.0085 (2)	−0.00057 (19)	0.00229 (18)	−0.00022 (18)
Ta6	0.0058 (2)	0.0053 (2)	0.0059 (2)	0.00013 (16)	0.00278 (16)	0.00015 (15)
Bi7	0.0073 (2)	0.0080 (2)	0.0074 (2)	−0.0010 (2)	0.0023 (2)	−0.0004 (2)
Ta8	0.0069 (2)	0.00494 (17)	0.0064 (2)	−0.00009 (16)	0.00363 (18)	−0.00013 (16)
Bi9	0.0107 (2)	0.0099 (3)	0.0100 (2)	−0.0000 (2)	0.0031 (2)	0.0000 (2)
Bi10	0.0180 (3)	0.0112 (3)	0.0174 (3)	−0.0040 (3)	0.0070 (3)	−0.0006 (2)
Bi11	0.0073 (2)	0.0139 (3)	0.0099 (2)	0.0003 (2)	0.0017 (2)	0.0002 (2)
Ta12	0.0047 (2)	0.0049 (2)	0.0059 (2)	−0.00043 (17)	0.00177 (17)	−0.00029 (16)
Bi13	0.0071 (2)	0.0086 (2)	0.0071 (2)	0.0006 (2)	0.00201 (18)	−0.00056 (19)
Bi14	0.0075 (2)	0.0119 (3)	0.0098 (2)	−0.0001 (2)	0.00397 (18)	−0.0000 (2)
Ta15	0.0073 (2)	0.00481 (16)	0.0070 (2)	−0.00018 (15)	0.00411 (17)	0.00023 (15)
Bi16	0.0077 (3)	0.0103 (2)	0.0076 (2)	0.0001 (2)	0.0013 (2)	−0.0005 (2)
Bi17	0.0081 (2)	0.0118 (3)	0.0094 (2)	−0.0001 (2)	0.00276 (19)	−0.0003 (2)
Ta18	0.0054 (2)	0.0049 (2)	0.0060 (2)	−0.00068 (17)	0.00248 (17)	−0.00049 (16)
Bi19	0.0085 (2)	0.0101 (2)	0.0069 (2)	−0.0005 (2)	0.00247 (19)	−0.0000 (2)
Bi20	0.0064 (2)	0.0103 (2)	0.0082 (2)	−0.0003 (2)	0.00202 (19)	0.0004 (2)

Geometric parameters (Å, º) top

Bi1—O17ⁱ	2.249 (11)	Bi11—O12^v	2.075 (9)
Bi1—O34ⁱⁱ	2.317 (11)	Bi11—O7^v	2.273 (11)
Bi1—O15	2.413 (8)	Bi11—O8^v	2.341 (11)
Bi2—O19	2.225 (9)	Bi11—O29	2.456 (10)
Bi2—O4ⁱⁱⁱ	2.234 (11)	Ta12—O36^vi	1.873 (10)
Bi2—O2	2.268 (11)	Ta12—O30	1.893 (11)
Bi2—O34	2.359 (10)	Ta12—O18	1.947 (10)
Bi3—O32	2.198 (12)	Ta12—O23	1.986 (9)
Bi3—O31	2.213 (11)	Ta12—O3	2.092 (9)
Bi3—O17	2.254 (9)	Ta12—O27	2.108 (10)
Ta4—O7	1.927 (10)	Bi13—O13^v	2.166 (10)
Ta4—O14^iv	1.966 (10)	Bi13—O15^v	2.247 (9)
Ta4—O4	1.978 (10)	Bi13—O24^v	2.259 (10)
Ta4—O1	1.987 (9)	Bi13—O17	2.409 (10)
Ta4—O36	2.001 (10)	Bi14—O21	2.018 (9)
Ta4—O29	2.069 (10)	Bi14—O6^v	2.243 (10)
Bi5—O5	2.247 (8)	Bi14—O27^v	2.247 (10)
Bi5—O16^iv	2.306 (10)	Ta15—O33	1.885 (12)
Bi5—O6	2.322 (9)	Ta15—O20	1.962 (10)
Bi5—O25ⁱⁱ	2.424 (11)	Ta15—O11	1.975 (10)
Ta6—O8	1.881 (11)	Ta15—O28^iv	2.015 (9)
Ta6—O14	1.946 (10)	Ta15—O31	2.020 (10)
Ta6—O10	1.962 (10)	Ta15—O15	2.092 (9)
Ta6—O1	2.008 (9)	Bi16—O34ⁱ	2.169 (10)
Ta6—O2	2.019 (10)	Bi16—O35ⁱ	2.193 (11)
Ta6—O9	2.111 (9)	Bi16—O33^vii	2.277 (12)
Bi7—O16	2.162 (9)	Bi17—O25ⁱ	2.064 (10)
Bi7—O22	2.174 (11)	Bi17—O26^vii	2.249 (10)
Bi7—O20ⁱⁱⁱ	2.192 (10)	Bi17—O30ⁱ	2.273 (11)
Ta8—O28	1.965 (9)	Ta18—O10^viii	1.899 (10)
Ta8—O35	1.969 (11)	Ta18—O26	1.900 (10)
Ta8—O22	1.981 (11)	Ta18—O23^iv	1.984 (9)
Ta8—O11	1.996 (10)	Ta18—O18	1.985 (10)
Ta8—O13	2.000 (10)	Ta18—O5	2.077 (9)
Ta8—O32	2.006 (11)	Ta18—O6	2.110 (9)
Bi9—O27	2.268 (9)	Bi19—O24	2.218 (10)
Bi9—O3	2.282 (9)	Bi19—O3	2.302 (10)
Bi9—O16	2.292 (10)	Bi19—O5	2.313 (9)
Bi9—O25ⁱ	2.319 (11)	Bi19—O21	2.372 (9)
Bi10—O12^v	2.303 (10)	Bi20—O19	2.078 (9)
Bi10—O9	2.314 (9)	Bi20—O29^vii	2.141 (10)
Bi10—O2	2.414 (9)	Bi20—O9ⁱ	2.220 (10)

O17ⁱ—Bi1—O34ⁱⁱ	110.5 (4)	O33—Ta15—O20	97.1 (4)
O17ⁱ—Bi1—O15	75.3 (3)	O33—Ta15—O11	92.6 (4)
O34ⁱⁱ—Bi1—O15	77.4 (3)	O33—Ta15—O28^iv	92.5 (4)
O19—Bi2—O4ⁱⁱⁱ	92.3 (4)	O33—Ta15—O31	91.5 (5)
O19ⁱⁱⁱ—Bi2—O2	90.4 (4)	O33—Ta15—O15	171.7 (4)
O19ⁱⁱⁱ—Bi2—O34	164.7 (4)	O20—Ta15—O11	88.8 (4)
O4ⁱⁱⁱ—Bi2—O2	88.5 (4)	O20—Ta15—O28^iv	90.7 (4)
O4ⁱⁱⁱ—Bi2—O34	77.0 (4)	O20—Ta15—O31	171.3 (4)
O2—Bi2—O34	78.6 (4)	O20—Ta15—O15	90.7 (4)
O32—Bi3—O31	88.2 (4)	O11—Ta15—O28^iv	174.9 (4)
O32—Bi3—O17	97.0 (4)	O11—Ta15—O31	92.4 (4)
O31—Bi3—O17	95.4 (4)	O11—Ta15—O15	90.4 (4)
O7^iv—Ta4—O14	89.1 (4)	O28^iv—Ta15—O31	87.3 (4)
O7—Ta4—O4	94.0 (4)	O28^iv—Ta15—O15	84.5 (3)
O7—Ta4—O1	92.2 (4)	O31—Ta15—O15	80.6 (4)
O7—Ta4—O36	100.3 (4)	O34ⁱ—Bi16—O35ⁱ	90.0 (4)
O7—Ta4—O29	174.6 (4)	O34ⁱ—Bi16—O33^vii	89.8 (4)
O14^iv—Ta4—O4	90.2 (4)	O35ⁱ—Bi16—O33^vii	85.3 (4)
O14^iv—Ta4—O1	178.7 (4)	O25ⁱ—Bi17—O26^vii	88.4 (4)
O14^iv—Ta4—O36	91.0 (4)	O25ⁱ—Bi17—O30ⁱ	89.1 (4)
O14^iv—Ta4—O29	94.2 (4)	O26^vii—Bi17—O30ⁱ	85.8 (4)
O4—Ta4—O1	89.5 (4)	O10^viii—Ta18—O26	103.0 (4)
O4—Ta4—O36	165.6 (4)	O10^viii—Ta18—O23^iv	92.2 (4)
O4—Ta4—O29	81.7 (4)	O10^viii—Ta18—O18	95.3 (4)
O1—Ta4—O36	89.0 (4)	O10^viii—Ta18—O5	161.6 (4)
O1—Ta4—O29	84.4 (4)	O10^viii—Ta18—O6	85.0 (4)
O36—Ta4—O29	83.9 (4)	O26—Ta18—O23^iv	91.0 (4)
O5—Bi5—O16^iv	78.7 (3)	O26—Ta18—O18	88.8 (4)
O5—Bi5—O6	69.3 (3)	O26—Ta18—O5	95.2 (4)
O5—Bi5—O25ⁱⁱ	113.9 (3)	O26—Ta18—O6	170.7 (4)
O16^iv—Bi5—O6	114.9 (3)	O23^iv—Ta18—O18	172.4 (4)
O16^iv—Bi5—O25ⁱⁱ	70.7 (4)	O23^iv—Ta18—O5	84.8 (3)
O6—Bi5—O25ⁱⁱ	73.2 (3)	O23^iv—Ta18—O6	83.7 (3)
O8—Ta6—O14	91.0 (4)	O18—Ta18—O5	87.6 (4)
O8—Ta6—O10	102.7 (4)	O18—Ta18—O6	95.4 (4)
O8—Ta6—O1	92.4 (4)	O5—Ta18—O6	76.7 (4)
O8—Ta6—O2	96.5 (4)	O24—Bi19—O3	79.5 (4)
O8—Ta6—O9	171.6 (4)	O24—Bi19—O5	76.7 (3)
O14—Ta6—O10	91.9 (4)	O24—Bi19—O21	161.1 (4)
O14—Ta6—O1	176.0 (3)	O3—Bi19—O5	88.4 (3)
O14—Ta6—O2	90.2 (4)	O3—Bi19—O21	89.1 (3)
O14—Ta6—O9	94.1 (4)	O5—Bi19—O21	88.1 (3)
O10—Ta6—O1	89.4 (4)	O19—Bi20—O29^vii	85.7 (4)
O10—Ta6—O2	160.6 (4)	O19—Bi20—O9ⁱ	80.0 (4)
O10—Ta6—O9	83.8 (4)	O29^vii—Bi20—O9ⁱ	93.6 (4)
O1—Ta6—O2	87.3 (4)	Ta4—O1—Ta6	145.7 (4)
O1—Ta6—O9	82.3 (4)	Ta6—O2—Bi2	133.3 (4)
O2—Ta6—O9	76.8 (4)	Ta6—O2—Bi10	106.2 (5)
O16—Bi7—O22	94.8 (4)	Bi2—O2—Bi10	107.0 (3)
O16—Bi7—O20ⁱⁱⁱ	90.7 (3)	Ta12—O3—Bi9	105.1 (5)
O22—Bi7—O20ⁱⁱⁱ	90.8 (4)	Ta12—O3—Bi19	133.2 (4)
O28—Ta8—O35	91.9 (4)	Bi9—O3—Bi19	107.7 (3)
O28—Ta8—O22	91.3 (4)	Ta4—O4—Bi2^iv	135.7 (5)
O28—Ta8—O11	176.6 (4)	Ta18—O5—Bi5	106.8 (4)
O28—Ta8—O13	86.4 (4)	Ta18—O5—Bi19	133.5 (4)
O28—Ta8—O32	89.7 (4)	Bi5—O5—Bi19	107.1 (3)
O35—Ta8—O22	93.9 (4)	Ta18—O6—Bi14ⁱ	131.7 (4)
O35—Ta8—O11	91.4 (4)	Ta18—O6—Bi5	103.0 (4)
O35—Ta8—O13	176.7 (4)	Bi14ⁱ—O6—Bi5	108.1 (3)
O35—Ta8—O32	89.3 (5)	Ta4—O7—Bi11ⁱ	150.4 (5)
O22—Ta8—O11	87.9 (4)	Ta6—O8—Bi11ⁱ	149.6 (5)
O22—Ta8—O13	89.1 (4)	Ta6—O9—Bi20^v	131.0 (4)
O22—Ta8—O32	176.7 (4)	Ta6—O9—Bi10	106.8 (5)
O11—Ta8—O13	90.3 (4)	Bi20^v—O9—Bi10	106.7 (3)
O11—Ta8—O32	91.0 (4)	Ta18^ix—O10—Ta6	165.3 (6)
O13—Ta8—O32	87.8 (4)	Ta15—O11—Ta8	148.8 (4)
O27—Bi9—O3	69.1 (4)	Bi11ⁱ—O12—Bi10ⁱ	114.3 (4)
O27—Bi9—O16	116.5 (3)	Ta8—O13—Bi13ⁱ	141.7 (5)
O27—Bi9—O25ⁱ	74.8 (3)	Ta6—O14—Ta4ⁱⁱⁱ	150.9 (5)
O3—Bi9—O16	77.1 (3)	Ta15—O15—Bi13ⁱ	134.6 (4)
O3—Bi9—O25ⁱ	114.5 (3)	Ta15—O15—Bi1	109.6 (4)
O16—Bi9—O25ⁱ	72.8 (4)	Bi13ⁱ—O15—Bi1	104.0 (3)
O12^v—Bi10—O9	74.9 (3)	Bi7—O16—Bi9	111.3 (4)
O12^v—Bi10—O2	112.0 (3)	Bi7—O16—Bi5ⁱⁱⁱ	110.1 (4)
O9—Bi10—O2	65.8 (4)	Bi9—O16—Bi5ⁱⁱⁱ	110.7 (4)
O12^v—Bi11—O7^v	89.3 (4)	Bi1^v—O17—Bi3	115.0 (4)
O12^v—Bi11—O8^v	86.5 (4)	Bi1^v—O17—Bi13	104.0 (4)
O12^v—Bi11—O29	80.9 (3)	Bi3—O17—Bi13	113.7 (5)
O7^v—Bi11—O8^v	82.3 (4)	Ta12—O18—Ta18	152.7 (5)
O7^v—Bi11—O29	75.1 (4)	Bi20—O19—Bi2	133.4 (6)
O8^v—Bi11—O29	154.2 (3)	Ta15—O20—Bi7^iv	143.5 (5)
O36^vi—Ta12—O30	102.9 (4)	Bi14—O21—Bi19	135.1 (6)
O36^vi—Ta12—O18	95.6 (4)	Ta8—O22—Bi7	144.0 (5)
O36^vi—Ta12—O23	92.5 (4)	Ta18ⁱⁱⁱ—O23—Ta12	144.6 (4)
O36^vi—Ta12—O3	160.2 (4)	Bi19—O24—Bi13ⁱ	119.1 (5)
O36^vi—Ta12—O27	84.4 (4)	Bi17^v—O25—Bi9^v	113.9 (4)
O30—Ta12—O18	87.2 (4)	Bi17^v—O25—Bi5^x	111.5 (4)
O30—Ta12—O23	92.1 (4)	Bi9^v—O25—Bi5^x	105.7 (5)
O30—Ta12—O3	96.7 (4)	Ta18—O26—Bi17^xi	148.1 (5)
O30—Ta12—O27	172.2 (4)	Ta12—O27—Bi14ⁱ	131.7 (4)
O18—Ta12—O23	171.7 (4)	Ta12—O27—Bi9	105.1 (5)
O18—Ta12—O3	88.0 (4)	Bi14ⁱ—O27—Bi9	109.6 (4)
O18—Ta12—O27	94.9 (4)	Ta8—O28—Ta15ⁱⁱⁱ	143.4 (4)
O23—Ta12—O3	83.9 (4)	Ta4—O29—Bi20^xi	134.9 (5)
O23—Ta12—O27	84.8 (4)	Ta4—O29—Bi11	103.2 (4)
O3—Ta12—O27	75.8 (4)	Bi20^xi—O29—Bi11	108.6 (5)
O13^v—Bi13—O15^v	90.0 (4)	Ta12—O30—Bi17^v	146.7 (5)
O13^v—Bi13—O24^v	91.8 (4)	Ta15—O31—Bi3	139.3 (5)
O13^v—Bi13—O17	83.7 (4)	Ta8—O32—Bi3	141.2 (5)
O15^v—Bi13—O24^v	94.6 (3)	Ta15—O33—Bi16^xi	147.7 (6)
O15^v—Bi13—O17	75.4 (3)	Bi16^v—O34—Bi1^x	112.1 (4)
O24^v—Bi13—O17	169.0 (4)	Bi16^v—O34—Bi2	111.8 (5)
O21—Bi14—O6^v	81.3 (4)	Bi1^x—O34—Bi2	107.2 (4)
O21—Bi14—O27^v	80.3 (4)	Ta8—O35—Bi16^v	147.9 (6)
O6^v—Bi14—O27^v	91.9 (4)	Ta12^xii—O36—Ta4	164.9 (6)

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

(pow) bismuth tantalum oxide top

Crystal data top

Bi₇Ta₃O₁₈	Z = 4
M_r = 2293.71	Neutron radiation, λ = ? Å
Monoclinic, C2/m	T = 293 K
a = 34.0084 (9) Å	Particle morphology: plate
b = 7.6069 (2) Å	yellow
c = 6.63644 (17) Å	cylinder, 25 × 8 mm
β = 109.2375 (11)°	Specimen preparation: Prepared at 1173 K and 101.3 kPa
V = 1620.94 (7) Å³

Data collection top

3He gas and ZnS scintillation counters diffractometer	Specimen mounting: vanadium can
Radiation source: spallation

Refinement top

R_p = 0.046	? data points
R_wp = 0.034	Profile function: exponential pseudo-Voigt convolution Von Dreele 1990 (unpublished)
R_exp = ?	116 parameters
χ² = 29.268

Crystal data top

Bi₇Ta₃O₁₈	β = 109.2375 (11)°
M_r = 2293.71	V = 1620.94 (7) Å³
Monoclinic, C2/m	Z = 4
a = 34.0084 (9) Å	Neutron radiation, λ = ? Å
b = 7.6069 (2) Å	T = 293 K
c = 6.63644 (17) Å	cylinder, 25 × 8 mm

Data collection top

3He gas and ZnS scintillation counters
diffractometer

Specimen mounting: vanadium can

Refinement top

R_p = 0.046	χ² = 29.268
R_wp = 0.034	? data points
R_exp = ?	116 parameters

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

	x	y	z	U_iso*/U_eq
Bi1	0.24592 (12)	0.5	0.4693 (6)	0.0114 (7)*
Bi2	0.14509 (7)	0.2522 (4)	0.4641 (3)	0.0154 (5)*
Bi3	0.14788 (9)	0.5	0.9794 (5)	0.0019 (6)*
Ta4	0.05535 (7)	0.2490 (3)	0.9919 (4)	0.0011 (4)*
Bi5	0.04985 (10)	0.5	0.4544 (6)	0.0234 (11)*
Ta6	0.25	0.25	0.0	0.0032 (8)*
Bi7	0.16126 (10)	0.0	0.0205 (5)	0.0119 (6)*
Bi8	0.05314 (9)	0.0	0.5117 (5)	0.0043 (6)*
O9	0.07053 (12)	0.5	0.0872 (5)	0.0016 (8)*
O10	0.11913 (9)	0.2017 (4)	0.0979 (5)	0.0085 (7)*
O11	0.04957 (9)	0.2973 (4)	0.7019 (4)	0.0064 (6)*
O12	0.07096 (9)	0.2109 (5)	0.3232 (5)	0.0106 (7)*
O13	0.04746 (14)	0.0	0.9260 (7)	0.0098 (10)*
O14	0.0	0.2889 (5)	0.0	0.0026 (7)*
O15	0.23936 (13)	0.2937 (7)	0.6883 (7)	0.0436 (13)*
O16	0.23930 (15)	0.0	0.9454 (8)	0.0140 (10)*
O17	0.16979 (15)	0.5	0.3363 (8)	0.0131 (10)*
O18	0.18926 (11)	0.2898 (5)	0.9466 (6)	0.0223 (9)*
O19	0.11791 (16)	0.0	0.6697 (8)	0.0206 (12)*
O20	0.11376 (13)	0.5	0.5550 (7)	0.0035 (8)*
O21	0.18336 (13)	0.0	0.3733 (7)	0.0086 (8)*

Experimental details

	(XTL)	(pow)
Crystal data
Chemical formula	Bi₇O₁₈Ta₃	Bi₇Ta₃O₁₈
M_r	2293.71	2293.71
Crystal system, space group	Triclinic, C1	Monoclinic, C2/m
Temperature (K)	293	293
a, b, c (Å)	34.005 (3), 7.6024 (4), 6.6358 (5)	34.0084 (9), 7.6069 (2), 6.63644 (17)
α, β, γ (°)	90.086 (6), 109.127 (6), 90.043 (6)	90, 109.2375 (11), 90
V (Å³)	1620.8 (2)	1620.94 (7)
Z	4	4
Radiation type	Synchrotron, λ = 0.9580 (4) Å	Neutron, λ = ? Å
µ (mm⁻¹)	85.4	–
Specimen shape, size (mm)	0.02 × 0.02 × 0.002	Cylinder, 25 × 8

Data collection
Diffractometer	Tsukuba diffractometer	3He gas and ZnS scintillation counters diffractometer
Specimen mounting	–	Vanadium can
Data collection mode	–	?
Data collection method	?	?
Absorption correction	Gaussian	–
T_min, T_max	0.277, 0.844	–
No. of measured, independent and observed [refl observed if F² > 3.000 σ(F²)] reflections	0.176040+05, 0.137980+05, 0.117960+05	–
R_int	0.023	–
θ values (°)	θ_max = 50, θ_min = 1.7	2θ_min = ? 2θ_max = ? 2θ_step = ?
(sin θ/λ)_max (Å⁻¹)	0.800	–

Refinement
R factors and goodness of fit	R[F² > 2σ(F²)] = 0.039, wR(F²) = 0.0337, S = ?	R_p = 0.046, R_wp = 0.034, R_exp = ?, χ² = 29.268
No. of reflections/data points	0.117960+05	?
No. of parameters	327	116
No. of restraints	0	?
Δρ_max, Δρ_min (e Å⁻³)	5.80, −5.61	–

Computer programs: Xtal DIFDAT SORTRF ADDREF ABSORB, Xtal LSLS, GSAS, Xtal CIFIO.

Selected bond lengths (Å) for (xtl) top

Bi1—O17ⁱ	2.249 (11)	Bi11—O12^v	2.075 (9)
Bi1—O34ⁱⁱ	2.317 (11)	Bi11—O7^v	2.273 (11)
Bi1—O15	2.413 (8)	Bi11—O8^v	2.341 (11)
Bi2—O19	2.225 (9)	Bi11—O29	2.456 (10)
Bi2—O4ⁱⁱⁱ	2.234 (11)	Ta12—O36^vi	1.873 (10)
Bi2—O2	2.268 (11)	Ta12—O30	1.893 (11)
Bi2—O34	2.359 (10)	Ta12—O18	1.947 (10)
Bi3—O32	2.198 (12)	Ta12—O23	1.986 (9)
Bi3—O31	2.213 (11)	Ta12—O3	2.092 (9)
Bi3—O17	2.254 (9)	Ta12—O27	2.108 (10)
Ta4—O7	1.927 (10)	Bi13—O13^v	2.166 (10)
Ta4—O14^iv	1.966 (10)	Bi13—O15^v	2.247 (9)
Ta4—O4	1.978 (10)	Bi13—O24^v	2.259 (10)
Ta4—O1	1.987 (9)	Bi13—O17	2.409 (10)
Ta4—O36	2.001 (10)	Bi14—O21	2.018 (9)
Ta4—O29	2.069 (10)	Bi14—O6^v	2.243 (10)
Bi5—O5	2.247 (8)	Bi14—O27^v	2.247 (10)
Bi5—O16^iv	2.306 (10)	Ta15—O33	1.885 (12)
Bi5—O6	2.322 (9)	Ta15—O20	1.962 (10)
Bi5—O25ⁱⁱ	2.424 (11)	Ta15—O11	1.975 (10)
Ta6—O8	1.881 (11)	Ta15—O28^iv	2.015 (9)
Ta6—O14	1.946 (10)	Ta15—O31	2.020 (10)
Ta6—O10	1.962 (10)	Ta15—O15	2.092 (9)
Ta6—O1	2.008 (9)	Bi16—O34ⁱ	2.169 (10)
Ta6—O2	2.019 (10)	Bi16—O35ⁱ	2.193 (11)
Ta6—O9	2.111 (9)	Bi16—O33^vii	2.277 (12)
Bi7—O16	2.162 (9)	Bi17—O25ⁱ	2.064 (10)
Bi7—O22	2.174 (11)	Bi17—O26^vii	2.249 (10)
Bi7—O20ⁱⁱⁱ	2.192 (10)	Bi17—O30ⁱ	2.273 (11)
Ta8—O28	1.965 (9)	Ta18—O10^viii	1.899 (10)
Ta8—O35	1.969 (11)	Ta18—O26	1.900 (10)
Ta8—O22	1.981 (11)	Ta18—O23^iv	1.984 (9)
Ta8—O11	1.996 (10)	Ta18—O18	1.985 (10)
Ta8—O13	2.000 (10)	Ta18—O5	2.077 (9)
Ta8—O32	2.006 (11)	Ta18—O6	2.110 (9)
Bi9—O27	2.268 (9)	Bi19—O24	2.218 (10)
Bi9—O3	2.282 (9)	Bi19—O3	2.302 (10)
Bi9—O16	2.292 (10)	Bi19—O5	2.313 (9)
Bi9—O25ⁱ	2.319 (11)	Bi19—O21	2.372 (9)
Bi10—O12^v	2.303 (10)	Bi20—O19	2.078 (9)
Bi10—O9	2.314 (9)	Bi20—O29^vii	2.141 (10)
Bi10—O2	2.414 (9)	Bi20—O9ⁱ	2.220 (10)

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

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Format		BIBTeX
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		CIF
		SGML
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