Structure and phase transitions of LiTaOGeO₄

The structure of LiTaOGeO₄ has been refined using X-ray diffraction data collected at 293 K and at 173 K. The low-temperature structure is isostructural with LiTaOSiO₄ and closely related to the low-temperature structure of titanite, CaTiOSiO₄. Li occurs in a distorted tetrahedral coordination. The transition to the disordered structure, with space group symmetry C2/c, occurs at T_c = 231 (1) K. Li is disordered across two symmetry-equivalent positions and Ta is located at the centre of its coordination octahedron in this paraphase. The transition is continuous, and the thermal evolution of the order parameter is well approximated using a tricritical mean-field model. Anharmonic thermal displacement of the Li cation has been analyzed and its one-particle potential has been determined. The height of the potential barrier separating the two Li positions across a curved trajectory is close to RT_c, where R is the universal gas constant.

Computing details

For all compounds, program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997).

Figures

(ltgo_2)

Crystal data

GeLiO5Ta	F(000) = 592
Mr = 340.48	Dx = 5.655 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
a = 7.584 (4) Å	Cell parameters from 25 reflections
b = 8.0849 (14) Å	θ = 16.3–32.0°
c = 7.508 (2) Å	µ = 34.75 mm^−1
β = 119.69 (3)°	T = 173 K
V = 399.9 (2) Å^3	0.16 × 0.06 × 0.04 mm
Z = 4

Data collection

Radiation source: fine-focus sealed tube	1476 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.032
ω–2θ scan	θmax = 35.0°, θmin = 4.0°
Absorption correction: numerical ?	h = −12→10
Tmin = 0.123, Tmax = 0.28	k = −13→13
3561 measured reflections	l = 0→12
1732 independent reflections

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.021	w = 1/[σ^2(Fo^2) + (0.0188P)^2] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.047	(Δ/σ)max = 0.001
S = 1.04	Δρmax = 2.45 e Å^−3
1732 reflections	Δρmin = −2.70 e Å^−3
74 parameters	Extinction correction: SHELXL, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
0 restraints	Extinction coefficient: 0.0318 (7)

Special details

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

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

	x	y	z	Uiso*/Ueq
Li	0.7492 (14)	0.0605 (10)	0.7880 (16)	0.0151 (15)
Ta	0.74938 (2)	0.757943 (16)	0.50822 (2)	0.00332 (6)
Ge	0.25022 (6)	0.61127 (5)	0.25627 (6)	0.00363 (8)
O1	0.2492 (4)	0.1815 (3)	0.2479 (4)	0.0066 (5)
O21	0.5515 (5)	0.2543 (3)	0.1517 (5)	0.0066 (5)
O31	0.7476 (5)	−0.0124 (3)	0.0532 (5)	0.0071 (5)
O22	0.9495 (5)	0.2469 (3)	0.8501 (5)	0.0062 (5)
O32	0.7491 (5)	−0.0128 (3)	0.4327 (5)	0.0070 (5)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Li	0.020 (4)	0.005 (3)	0.024 (4)	0.004 (3)	0.014 (3)	0.006 (3)
Ta	0.00271 (7)	0.00405 (8)	0.00334 (8)	−0.00026 (4)	0.00160 (5)	0.00009 (4)
Ge	0.00319 (14)	0.00327 (14)	0.00455 (16)	−0.00010 (11)	0.00202 (12)	−0.00007 (11)
O1	0.0081 (12)	0.0046 (11)	0.0072 (12)	0.0010 (8)	0.0039 (10)	0.0015 (8)
O21	0.0038 (11)	0.0067 (12)	0.0079 (11)	0.0022 (7)	0.0018 (9)	0.0004 (8)
O31	0.0103 (12)	0.0048 (10)	0.0068 (11)	−0.0004 (9)	0.0047 (10)	−0.0020 (9)
O22	0.0047 (11)	0.0054 (12)	0.0089 (11)	0.0008 (7)	0.0037 (9)	0.0009 (8)
O32	0.0091 (12)	0.0054 (10)	0.0082 (12)	0.0003 (9)	0.0056 (10)	0.0020 (9)

Geometric parameters (Å, º)

Li—O1^i	1.976 (8)	Ge—O21^vii	1.745 (3)
Li—O21^ii	2.004 (9)	Ge—O22^iv	1.746 (3)
Li—O22	2.024 (9)	Ge—Li^iv	2.675 (8)
Li—O31^iii	2.082 (10)	O1—Ta^iv	1.890 (3)
Li—Ge^iv	2.675 (8)	O1—Li^i	1.976 (8)
Li—Ta^ii	3.059 (8)	O1—Ta^x	2.025 (3)
Li—Ta^v	3.225 (9)	O21—Ge^x	1.745 (3)
Ta—O1^iv	1.890 (3)	O21—Ta^x	1.984 (3)
Ta—O32^vi	1.938 (3)	O21—Li^ix	2.004 (9)
Ta—O21^vii	1.984 (3)	O31—Ge^x	1.739 (3)
Ta—O22^viii	1.987 (3)	O31—Ta^ix	2.015 (3)
Ta—O31^ii	2.015 (3)	O31—Li^xi	2.082 (10)
Ta—O1^vii	2.025 (3)	O22—Ge^iv	1.746 (3)
Ta—Li^ix	3.059 (8)	O22—Ta^xii	1.987 (3)
Ta—Li^vi	3.225 (9)	O32—Ge^x	1.739 (3)
Ge—O31^vii	1.739 (3)	O32—Ta^v	1.938 (3)
Ge—O32^vii	1.739 (3)
O1^i—Li—O21^ii	136.4 (5)	O1^iv—Ta—Li^ix	137.7 (2)
O1^i—Li—O22	135.6 (5)	O32^vi—Ta—Li^ix	130.3 (2)
O21^ii—Li—O22	81.2 (3)	O21^vii—Ta—Li^ix	88.2 (2)
O1^i—Li—O31^iii	81.6 (3)	O22^viii—Ta—Li^ix	86.80 (19)
O21^ii—Li—O31^iii	110.0 (4)	O31^ii—Ta—Li^ix	42.5 (2)
O22—Li—O31^iii	110.5 (5)	O1^vii—Ta—Li^ix	39.54 (19)
O1^i—Li—Ge^iv	164.8 (5)	O1^iv—Ta—Li^vi	34.33 (19)
O21^ii—Li—Ge^iv	40.73 (17)	O32^vi—Ta—Li^vi	57.64 (19)
O22—Li—Ge^iv	40.74 (16)	O21^vii—Ta—Li^vi	91.95 (19)
O31^iii—Li—Ge^iv	113.6 (4)	O22^viii—Ta—Li^vi	93.25 (19)
O1^i—Li—Ta^ii	40.72 (19)	O31^ii—Ta—Li^vi	129.49 (19)
O21^ii—Li—Ta^ii	134.8 (4)	O1^vii—Ta—Li^vi	148.43 (19)
O22—Li—Ta^ii	134.7 (4)	Li^ix—Ta—Li^vi	172.0 (3)
O31^iii—Li—Ta^ii	40.86 (17)	O31^vii—Ge—O32^vii	109.67 (15)
Ge^iv—Li—Ta^ii	154.5 (4)	O31^vii—Ge—O21^vii	113.59 (14)
O1^i—Li—Ta^v	32.64 (18)	O32^vii—Ge—O21^vii	110.78 (14)
O21^ii—Li—Ta^v	118.4 (4)	O31^vii—Ge—O22^iv	114.01 (14)
O22—Li—Ta^v	118.2 (4)	O32^vii—Ge—O22^iv	110.96 (14)
O31^iii—Li—Ta^v	114.2 (3)	O21^vii—Ge—O22^iv	97.35 (14)
Ge^iv—Li—Ta^v	132.1 (4)	O31^vii—Ge—Li^iv	132.3 (2)
Ta^ii—Li—Ta^v	73.36 (17)	O32^vii—Ge—Li^iv	118.0 (2)
O1^iv—Ta—O32^vi	91.97 (13)	O21^vii—Ge—Li^iv	48.5 (2)
O1^iv—Ta—O21^vii	92.48 (13)	O22^iv—Ge—Li^iv	49.2 (2)
O32^vi—Ta—O21^vii	90.16 (12)	Ta^iv—O1—Li^i	113.0 (3)
O1^iv—Ta—O22^viii	92.26 (13)	Ta^iv—O1—Ta^x	147.23 (16)
O32^vi—Ta—O22^viii	91.94 (11)	Li^i—O1—Ta^x	99.7 (3)
O21^vii—Ta—O22^viii	174.74 (10)	Ge^x—O21—Ta^x	139.16 (15)
O1^iv—Ta—O31^ii	95.16 (13)	Ge^x—O21—Li^ix	90.7 (3)
O32^vi—Ta—O31^ii	172.86 (11)	Ta^x—O21—Li^ix	130.0 (3)
O21^vii—Ta—O31^ii	89.17 (11)	Ge^x—O31—Ta^ix	134.95 (17)
O22^viii—Ta—O31^ii	88.14 (11)	Ge^x—O31—Li^xi	128.4 (3)
O1^iv—Ta—O1^vii	177.18 (6)	Ta^ix—O31—Li^xi	96.6 (2)
O32^vi—Ta—O1^vii	90.79 (12)	Ge^iv—O22—Ta^xii	136.22 (14)
O21^vii—Ta—O1^vii	88.07 (12)	Ge^iv—O22—Li	90.1 (3)
O22^viii—Ta—O1^vii	87.08 (12)	Ta^xii—O22—Li	133.6 (3)
O31^ii—Ta—O1^vii	82.08 (12)	Ge^x—O32—Ta^v	142.18 (17)

Symmetry codes: (i) −x+1, −y, −z+1; (ii) x, −y+1/2, z+1/2; (iii) x, y, z+1; (iv) −x+1, −y+1, −z+1; (v) x, y−1, z; (vi) x, y+1, z; (vii) −x+1, y+1/2, −z+1/2; (viii) −x+2, y+1/2, −z+3/2; (ix) x, −y+1/2, z−1/2; (x) −x+1, y−1/2, −z+1/2; (xi) x, y, z−1; (xii) −x+2, y−1/2, −z+3/2.

(ltgo_amb)

Crystal data

GeLiO5Ta	F(000) = 592
Mr = 340.48	Dx = 5.641 Mg m^−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
a = 7.5773 (1) Å	Cell parameters from 164 reflections
b = 8.1188 (1) Å	θ = 8.7–44.7°
c = 7.4910 (1) Å	µ = 34.67 mm^−1
β = 119.545 (1)°	T = 293 K
V = 400.91 (1) Å^3	0.16 × 0.06 × 0.04 mm
Z = 4

Data collection

Radiation source: fine-focus sealed tube	776 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.023
ω–2θ scan	θmax = 34.9°, θmin = 4.0°
Absorption correction: numerical ?	h = −12→10
Tmin = 0.071, Tmax = 0.345	k = −13→13
1809 measured reflections	l = 0→12
877 independent reflections

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.016	w = 1/[σ^2(Fo^2) + (0.0217P)^2] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.037	(Δ/σ)max < 0.001
S = 1.04	Δρmax = 1.94 e Å^−3
877 reflections	Δρmin = −2.45 e Å^−3
41 parameters	Extinction correction: SHELXL, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
0 restraints	Extinction coefficient: 0.0364 (10)

Special details

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

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

	x	y	z	Uiso*/Ueq
Li	0.0000	0.3128 (17)	0.7500	0.039 (4)
Ta	0.0000	0.0000	0.0000	0.00571 (8)
Ge	0.0000	0.36046 (6)	0.2500	0.00576 (10)
O1	0.0000	0.0673 (4)	0.7500	0.0090 (5)
O2	0.1991 (4)	0.4985 (2)	0.8505 (4)	0.0098 (4)
O3	0.0008 (3)	0.2369 (3)	0.0600 (4)	0.0104 (4)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Li	0.026 (6)	0.015 (5)	0.064 (10)	0.000	0.014 (6)	0.000
Ta	0.00389 (9)	0.00752 (10)	0.00527 (10)	0.00053 (4)	0.00192 (6)	−0.00117 (5)
Ge	0.00458 (16)	0.00481 (16)	0.00725 (19)	0.000	0.00244 (13)	0.000
O1	0.0141 (14)	0.0100 (13)	0.0056 (13)	0.000	0.0068 (11)	0.000
O2	0.0039 (7)	0.0099 (9)	0.0127 (10)	0.0012 (6)	0.0019 (7)	0.0011 (7)
O3	0.0151 (9)	0.0072 (8)	0.0099 (9)	−0.0005 (7)	0.0069 (8)	−0.0020 (7)

Geometric parameters (Å, º)

Li—O1	1.994 (15)	Ta—O2^ix	1.984 (2)
Li—O2	1.998 (11)	Ta—Li^v	3.156 (11)
Li—O2^i	1.998 (11)	Ta—Li^vi	3.156 (11)
Li—O3^ii	2.400 (4)	Ge—O3^iii	1.744 (2)
Li—O3^iii	2.400 (4)	Ge—O3	1.744 (2)
Li—Ge^iv	2.653 (14)	Ge—O2^iv	1.742 (2)
Li—Ta^ii	3.156 (11)	Ge—O2^x	1.742 (2)
Li—Ta^iii	3.156 (11)	Ge—Li^iv	2.653 (14)
Ta—O1^v	1.9507 (9)	O1—Ta^ii	1.9507 (9)
Ta—O1^vi	1.9507 (9)	O1—Ta^iii	1.9507 (9)
Ta—O3	1.974 (2)	O2—Ge^iv	1.742 (2)
Ta—O3^vii	1.974 (2)	O2—Ta^xi	1.984 (2)
Ta—O2^viii	1.984 (2)	O3—Li^vi	2.400 (4)
O1—Li—O2	139.0 (3)	O1^v—Ta—O2^ix	90.21 (8)
O1—Li—O2^i	139.0 (3)	O1^vi—Ta—O2^ix	89.79 (8)
O2—Li—O2^i	82.1 (5)	O3—Ta—O2^ix	89.52 (9)
O1—Li—O3^ii	75.1 (3)	O3^vii—Ta—O2^ix	90.48 (9)
O2—Li—O3^ii	100.8 (2)	O2^viii—Ta—O2^ix	180.00 (11)
O2^i—Li—O3^ii	101.5 (2)	O1^v—Ta—Li^v	37.34 (18)
O1—Li—O3^iii	75.1 (3)	O1^vi—Ta—Li^v	142.66 (18)
O2—Li—O3^iii	101.5 (2)	O3—Ta—Li^v	130.53 (17)
O2^i—Li—O3^iii	100.8 (2)	O3^vii—Ta—Li^v	49.47 (17)
O3^ii—Li—O3^iii	150.2 (7)	O2^viii—Ta—Li^v	89.64 (7)
O1—Li—Ge^iv	180.0	O2^ix—Ta—Li^v	90.36 (7)
O2—Li—Ge^iv	41.0 (3)	O1^v—Ta—Li^vi	142.66 (18)
O2^i—Li—Ge^iv	41.0 (3)	O1^vi—Ta—Li^vi	37.34 (18)
O3^ii—Li—Ge^iv	104.9 (3)	O3—Ta—Li^vi	49.47 (17)
O3^iii—Li—Ge^iv	104.9 (3)	O3^vii—Ta—Li^vi	130.53 (17)
O1—Li—Ta^ii	36.40 (15)	O2^viii—Ta—Li^vi	90.36 (7)
O2—Li—Ta^ii	127.19 (12)	O2^ix—Ta—Li^vi	89.64 (7)
O2^i—Li—Ta^ii	127.56 (12)	Li^v—Ta—Li^vi	180.0
O3^ii—Li—Ta^ii	38.71 (18)	O3^iii—Ge—O3	109.75 (15)
O3^iii—Li—Ta^ii	111.5 (5)	O3^iii—Ge—O2^iv	112.34 (12)
Ge^iv—Li—Ta^ii	143.60 (15)	O3—Ge—O2^iv	112.12 (12)
O1—Li—Ta^iii	36.40 (15)	O3^iii—Ge—O2^x	112.12 (12)
O2—Li—Ta^iii	127.56 (12)	O3—Ge—O2^x	112.34 (12)
O2^i—Li—Ta^iii	127.19 (12)	O2^iv—Ge—O2^x	97.77 (15)
O3^ii—Li—Ta^iii	111.5 (5)	O3^iii—Ge—Li^iv	125.12 (8)
O3^iii—Li—Ta^iii	38.71 (18)	O3—Ge—Li^iv	125.12 (8)
Ge^iv—Li—Ta^iii	143.60 (15)	O2^iv—Ge—Li^iv	48.89 (7)
Ta^ii—Li—Ta^iii	72.8 (3)	O2^x—Ge—Li^iv	48.89 (7)
O1^v—Ta—O1^vi	180.00 (18)	Ta^ii—O1—Ta^iii	147.49 (18)
O1^v—Ta—O3	93.19 (12)	Ta^ii—O1—Li	106.26 (9)
O1^vi—Ta—O3	86.81 (12)	Ta^iii—O1—Li	106.26 (9)
O1^v—Ta—O3^vii	86.81 (12)	Ge^iv—O2—Ta^xi	138.53 (12)
O1^vi—Ta—O3^vii	93.19 (12)	Ge^iv—O2—Li	90.1 (3)
O3—Ta—O3^vii	180.0	Ta^xi—O2—Li	131.4 (3)
O1^v—Ta—O2^viii	89.79 (8)	Ge—O3—Ta	138.19 (14)
O1^vi—Ta—O2^viii	90.21 (8)	Ge—O3—Li^vi	130.0 (3)
O3—Ta—O2^viii	90.48 (9)	Ta—O3—Li^vi	91.8 (3)
O3^vii—Ta—O2^viii	89.52 (9)

Symmetry codes: (i) −x, y, −z+3/2; (ii) x, y, z+1; (iii) −x, y, −z+1/2; (iv) −x, −y+1, −z+1; (v) −x, −y, −z+1; (vi) x, y, z−1; (vii) −x, −y, −z; (viii) x−1/2, y−1/2, z−1; (ix) −x+1/2, −y+1/2, −z+1; (x) x, −y+1, z−1/2; (xi) x+1/2, y+1/2, z+1.

(ltgo_amb_split)

Crystal data

GeLiO5Ta	F(000) = 592
Mr = 340.48	Dx = 5.641 Mg m^−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
a = 7.5773 (1) Å	Cell parameters from 164 reflections
b = 8.1188 (1) Å	θ = 8.7–44.7°
c = 7.4910 (1) Å	µ = 34.67 mm^−1
β = 119.545 (1)°	T = 293 K
V = 400.91 (1) Å^3	0.16 × 0.06 × 0.04 mm
Z = 4

Data collection

Radiation source: fine-focus sealed tube	776 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.023
ω–2θ scan	θmax = 34.9°, θmin = 4.0°
Absorption correction: numerical ?	h = −12→10
Tmin = 0.071, Tmax = 0.345	k = −13→13
1809 measured reflections	l = 0→12
877 independent reflections

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.016	w = 1/[σ^2(Fo^2) + (0.0213P)^2] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.037	(Δ/σ)max < 0.001
S = 1.04	Δρmax = 1.94 e Å^−3
877 reflections	Δρmin = −2.43 e Å^−3
40 parameters	Extinction correction: SHELXL, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
0 restraints	Extinction coefficient: 0.0367 (9)

Special details

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

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

	x	y	z	Uiso*/Ueq	Occ. (<1)
Li	0.001 (3)	0.3133 (17)	0.781 (2)	0.018 (3)*	0.50
Ta	0.0000	0.0000	0.0000	0.00573 (8)
Ge	0.0000	0.36046 (6)	0.2500	0.00578 (10)
O1	0.0000	0.0673 (4)	0.7500	0.0091 (5)
O2	0.1990 (4)	0.4985 (2)	0.8504 (4)	0.0098 (4)
O3	0.0008 (3)	0.2369 (3)	0.0600 (4)	0.0104 (4)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Ta	0.00390 (9)	0.00754 (9)	0.00531 (10)	0.00053 (4)	0.00192 (6)	−0.00117 (5)
Ge	0.00458 (16)	0.00482 (16)	0.00730 (18)	0.000	0.00243 (13)	0.000
O1	0.0140 (13)	0.0099 (13)	0.0057 (13)	0.000	0.0068 (11)	0.000
O2	0.0039 (7)	0.0099 (8)	0.0127 (10)	0.0013 (6)	0.0019 (7)	0.0011 (7)
O3	0.0151 (9)	0.0073 (8)	0.0099 (9)	−0.0005 (7)	0.0069 (8)	−0.0022 (7)

Geometric parameters (Å, º)

Li—Li^i	0.45 (3)	Ta—Li^iii	3.298 (12)
Li—O2	2.002 (16)	Ta—Li^x	3.298 (12)
Li—O1	2.010 (14)	Ge—O2^xi	1.742 (2)
Li—O2^i	2.014 (16)	Ge—O2^iv	1.742 (2)
Li—O3^ii	2.183 (15)	Ge—O3	1.744 (2)
Li—O3^iii	2.619 (14)	Ge—O3^iii	1.744 (2)
Li—Ge^iv	2.658 (14)	Ge—Li^xi	2.658 (14)
Li—Ta^ii	3.030 (15)	Ge—Li^iv	2.658 (14)
Li—Ta^iii	3.298 (12)	O1—Ta^iii	1.9508 (9)
Ta—O1^v	1.9508 (9)	O1—Ta^ii	1.9508 (9)
Ta—O1^vi	1.9508 (9)	O1—Li^i	2.010 (14)
Ta—O3	1.974 (2)	O2—Ge^iv	1.742 (2)
Ta—O3^vii	1.974 (2)	O2—Ta^xii	1.984 (2)
Ta—O2^viii	1.984 (2)	O2—Li^i	2.014 (16)
Ta—O2^ix	1.984 (2)	O3—Li^vi	2.183 (15)
Ta—Li^vi	3.030 (15)	O3—Li^iii	2.619 (14)
Ta—Li^v	3.030 (15)
Li^i—Li—O2	85 (3)	O1^v—Ta—Li^v	40.8 (3)
Li^i—Li—O1	83.5 (4)	O1^vi—Ta—Li^v	139.2 (3)
O2—Li—O1	137.4 (9)	O3—Ta—Li^v	134.0 (2)
Li^i—Li—O2^i	82 (3)	O3^vii—Ta—Li^v	46.0 (2)
O2—Li—O2^i	81.6 (5)	O2^viii—Ta—Li^v	90.5 (3)
O1—Li—O2^i	136.6 (9)	O2^ix—Ta—Li^v	89.5 (3)
Li^i—Li—O3^ii	163.4 (6)	Li^vi—Ta—Li^v	180.0 (3)
O2—Li—O3^ii	108.5 (7)	O1^v—Ta—Li^iii	145.8 (3)
O1—Li—O3^ii	79.9 (5)	O1^vi—Ta—Li^iii	34.2 (3)
O2^i—Li—O3^ii	108.9 (6)	O3—Ta—Li^iii	52.6 (3)
Li^i—Li—O3^iii	13.8 (6)	O3^vii—Ta—Li^iii	127.4 (3)
O2—Li—O3^iii	94.3 (6)	O2^viii—Ta—Li^iii	89.8 (3)
O1—Li—O3^iii	69.8 (4)	O2^ix—Ta—Li^iii	90.2 (3)
O2^i—Li—O3^iii	93.5 (6)	Li^vi—Ta—Li^iii	6.6 (4)
O3^ii—Li—O3^iii	149.8 (6)	Li^v—Ta—Li^iii	173.4 (4)
Li^i—Li—Ge^iv	85.1 (3)	O1^v—Ta—Li^x	34.2 (3)
O2—Li—Ge^iv	40.9 (3)	O1^vi—Ta—Li^x	145.8 (3)
O1—Li—Ge^iv	168.7 (7)	O3—Ta—Li^x	127.4 (3)
O2^i—Li—Ge^iv	40.9 (3)	O3^vii—Ta—Li^x	52.6 (3)
O3^ii—Li—Ge^iv	111.4 (5)	O2^viii—Ta—Li^x	90.2 (3)
O3^iii—Li—Ge^iv	98.8 (5)	O2^ix—Ta—Li^x	89.8 (3)
Li^i—Li—Ta^ii	122.9 (3)	Li^vi—Ta—Li^x	173.4 (4)
O2—Li—Ta^ii	133.7 (7)	Li^v—Ta—Li^x	6.6 (4)
O1—Li—Ta^ii	39.4 (3)	Li^iii—Ta—Li^x	180.0 (3)
O2^i—Li—Ta^ii	133.5 (7)	O2^xi—Ge—O2^iv	97.76 (15)
O3^ii—Li—Ta^ii	40.6 (3)	O2^xi—Ge—O3	112.34 (12)
O3^iii—Li—Ta^ii	109.2 (4)	O2^iv—Ge—O3	112.12 (12)
Ge^iv—Li—Ta^ii	152.0 (5)	O2^xi—Ge—O3^iii	112.12 (12)
Li^i—Li—Ta^iii	50.5 (3)	O2^iv—Ge—O3^iii	112.34 (12)
O2—Li—Ta^iii	120.8 (6)	O3—Ge—O3^iii	109.76 (15)
O1—Li—Ta^iii	33.1 (2)	O2^xi—Ge—Li^xi	48.9 (4)
O2^i—Li—Ta^iii	120.0 (6)	O2^iv—Ge—Li^xi	49.2 (4)
O3^ii—Li—Ta^iii	113.0 (5)	O3—Ge—Li^xi	130.0 (3)
O3^iii—Li—Ta^iii	36.77 (17)	O3^iii—Ge—Li^xi	120.2 (3)
Ge^iv—Li—Ta^iii	135.6 (5)	O2^xi—Ge—Li^iv	49.2 (4)
Ta^ii—Li—Ta^iii	72.4 (3)	O2^iv—Ge—Li^iv	48.9 (4)
O1^v—Ta—O1^vi	180.00 (18)	O3—Ge—Li^iv	120.2 (3)
O1^v—Ta—O3	93.20 (12)	O3^iii—Ge—Li^iv	130.0 (3)
O1^vi—Ta—O3	86.80 (12)	Li^xi—Ge—Li^iv	9.8 (6)
O1^v—Ta—O3^vii	86.80 (12)	Ta^iii—O1—Ta^ii	147.48 (18)
O1^vi—Ta—O3^vii	93.20 (12)	Ta^iii—O1—Li	112.7 (4)
O3—Ta—O3^vii	180.0	Ta^ii—O1—Li	99.8 (4)
O1^v—Ta—O2^viii	90.22 (8)	Ta^iii—O1—Li^i	99.8 (4)
O1^vi—Ta—O2^viii	89.78 (8)	Ta^ii—O1—Li^i	112.7 (4)
O3—Ta—O2^viii	89.52 (9)	Li—O1—Li^i	12.9 (8)
O3^vii—Ta—O2^viii	90.48 (9)	Ge^iv—O2—Ta^xii	138.52 (12)
O1^v—Ta—O2^ix	89.78 (8)	Ge^iv—O2—Li	90.2 (5)
O1^vi—Ta—O2^ix	90.22 (8)	Ta^xii—O2—Li	131.0 (5)
O3—Ta—O2^ix	90.48 (9)	Ge^iv—O2—Li^i	89.8 (5)
O3^vii—Ta—O2^ix	89.52 (9)	Ta^xii—O2—Li^i	131.3 (5)
O2^viii—Ta—O2^ix	180.0	Li—O2—Li^i	12.9 (8)
O1^v—Ta—Li^vi	139.2 (3)	Ge—O3—Ta	138.18 (14)
O1^vi—Ta—Li^vi	40.8 (3)	Ge—O3—Li^vi	128.4 (4)
O3—Ta—Li^vi	46.0 (2)	Ta—O3—Li^vi	93.5 (3)
O3^vii—Ta—Li^vi	134.0 (2)	Ge—O3—Li^iii	131.2 (3)
O2^viii—Ta—Li^vi	89.5 (3)	Ta—O3—Li^iii	90.6 (3)
O2^ix—Ta—Li^vi	90.5 (3)	Li^vi—O3—Li^iii	2.8 (2)

Symmetry codes: (i) −x, y, −z+3/2; (ii) x, y, z+1; (iii) −x, y, −z+1/2; (iv) −x, −y+1, −z+1; (v) −x, −y, −z+1; (vi) x, y, z−1; (vii) −x, −y, −z; (viii) −x+1/2, −y+1/2, −z+1; (ix) x−1/2, y−1/2, z−1; (x) x, −y, z−1/2; (xi) x, −y+1, z−1/2; (xii) x+1/2, y+1/2, z+1.