Structural study of the low-temperature phase of TlH2PO4 at 180 K

Álvarez-Otero, E.; Madariaga, G.; Peral, I.; Folcia, C.L.; Ríos, S.

doi:10.1107/S0108768102010066

Structural study of the low-temperature phase of TlH₂PO₄ at 180 K

E. Álvarez-Otero, G. Madariaga, I. Peral, C. L. Folcia and S. Ríos

The low-temperature phase of TlH₂PO₄ has been studied by X-ray diffraction. A structural model is proposed with space group P $\bar 1$ . This model is compared with the structure of the antiferroelectric phase of TlD₂PO₄ at room temperature to analyze the expected isomorphism at low temperature. Given the structural distortion of TlH₂PO₄, such isomorphism present in the common high-temperature phase is not recovered in this phase. Through the analysis of the displacements of the PO₄ groups there is some evidence that the ordering of the H atoms responsible for the appearance of antiferroelectricity seems to be incomplete. An exhaustive study of the detected ferroelastic domains is also performed.

Keywords: TlH₂PO₄; X-ray diffraction; antiferroelectricity.

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Supporting information

	Crystallographic Information File (CIF) https://doi.org/10.1107/S0108768102010066/na0131sup1.cif Contains datablocks tdp180_1, tdp180_2, global
	Structure factor file (CIF format) https://doi.org/10.1107/S0108768102010066/na0131sup2.hkl Supplementary material

Computing details top

For both compounds, data collection: STOE IPDS; cell refinement: STOE IPDS; data reduction: STOE IPDS; program(s) used to solve structure: JANA2000 (Petricek et al., 2000); program(s) used to refine structure: JANA2000 (Petricel et al., 2000); software used to prepare material for publication: JANA2000 (Petricek et al., 2000).

Figures top

(tdp180_1) top

Crystal data top

Tl₄H₈P₄O₁₆	V = 830.7 (7) Å³
M_r = 1205.5	Z = 2
Triclinic, P1	F(000) = 1040
a = 8.997 (5) Å	D_x = 4.818 Mg m⁻³
b = 14.866 (6) Å	Mo Kα radiation, λ = 0.71073 Å
c = 6.499 (3) Å	µ = 39.14 mm⁻¹
α = 92.03 (3)°	T = 180 K
β = 89.92 (6)°	Irregular, colourless
γ = 107.01 (4)°	× × mm

Data collection top

Imaging plate diffractometer	1504 reflections with 3
phi–rotation scans	R_int = 0.085
Absorption correction: gaussian ?	θ_max = 26.0°, θ_min = 2.4°
T_min = 0.007, T_max = 0.046	h = −10→11
6004 measured reflections	k = −18→18
3017 independent reflections	l = −7→7

Refinement top

Refinement on F²	127 parameters
R[F² > 2σ(F²)] = 0.063	Weighting scheme based on measured s.u.'s w = 1/(σ²(I) + 0.0036I²)
wR(F²) = 0.180	(Δ/σ)_max = 0.240
S = 1.32	Δρ_max = 5.76 e Å⁻³
3017 reflections	Δρ_min = −5.20 e Å⁻³

Crystal data top

Tl₄H₈P₄O₁₆	γ = 107.01 (4)°
M_r = 1205.5	V = 830.7 (7) Å³
Triclinic, P1	Z = 2
a = 8.997 (5) Å	Mo Kα radiation
b = 14.866 (6) Å	µ = 39.14 mm⁻¹
c = 6.499 (3) Å	T = 180 K
α = 92.03 (3)°	× × mm
β = 89.92 (6)°

Data collection top

Imaging plate diffractometer	3017 independent reflections
Absorption correction: gaussian ?	1504 reflections with 3
T_min = 0.007, T_max = 0.046	R_int = 0.085
6004 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.063	127 parameters
wR(F²) = 0.180	(Δ/σ)_max = 0.240
S = 1.32	Δρ_max = 5.76 e Å⁻³
3017 reflections	Δρ_min = −5.20 e Å⁻³

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

	x	y	z	U_iso*/U_eq
Tl1	0.0687 (3)	0.13610 (17)	0.2609 (7)	0.0212 (8)
Tl2	0.4442 (3)	0.3741 (3)	−0.2799 (3)	0.0253 (9)
Tl3	0.5575 (3)	0.11916 (17)	0.2658 (7)	0.0221 (8)
Tl4	0.9466 (3)	0.3691 (3)	0.7635 (2)	0.0257 (9)
P1	0.1723 (17)	0.3758 (10)	0.240 (2)	0.0169 (8)*
O1a	0.286 (4)	0.430 (2)	0.060 (5)	0.024 (3)*
O2a	0.022 (4)	0.314 (2)	0.166 (6)	0.021 (3)*
O3a	0.136 (5)	0.452 (2)	0.385 (5)	0.017 (2)*
O4a	0.270 (4)	0.324 (2)	0.349 (4)	0.014 (2)*
P2	0.2985 (18)	0.1251 (12)	−0.232 (2)	0.0169 (8)*
O1b	0.337 (5)	0.080 (2)	−0.043 (5)	0.024 (3)*
O2b	0.203 (5)	0.194 (2)	−0.161 (5)	0.021 (3)*
O3b	0.187 (4)	0.053 (2)	−0.375 (5)	0.017 (2)*
O4b	0.447 (4)	0.179 (2)	−0.329 (4)	0.014 (2)*
P3	0.6716 (17)	0.3771 (10)	0.231 (2)	0.0169 (8)*
O1c	0.761 (5)	0.420 (2)	0.036 (5)	0.024 (3)*
O2c	0.517 (4)	0.303 (2)	0.180 (5)	0.021 (3)*
O3c	0.650 (4)	0.446 (2)	0.388 (5)	0.017 (2)*
O4c	0.773 (4)	0.319 (2)	0.327 (4)	0.014 (2)*
P4	0.7983 (18)	0.1228 (12)	−0.240 (2)	0.0169 (8)*
O1d	0.842 (5)	0.083 (2)	−0.040 (5)	0.024 (3)*
O2d	0.701 (5)	0.195 (2)	−0.166 (5)	0.021 (3)*
O3d	0.696 (4)	0.050 (2)	−0.384 (5)	0.017 (2)*
O4d	0.952 (4)	0.180 (2)	−0.326 (4)	0.014 (2)*
H1a	0.27 (2)	0.490 (16)	0.02 (7)	0.03*
H1b	0.22 (2)	0.49 (3)	0.48 (8)	0.03*
H1c	0.23 (2)	−0.019 (3)	0.01 (6)	0.03*
H1d	0.26 (4)	−0.01 (3)	−0.52 (4)	0.03*
H2a	−0.45 (2)	−0.81 (3)	−0.260 (18)	0.03*
H2b	−0.128 (14)	0.32 (4)	0.26 (2)	0.03*
H2c	−0.90 (3)	−0.81 (2)	−0.23 (7)	0.03*
H2d	−0.58 (2)	0.31 (4)	0.249 (15)	0.03*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Tl1	0.0273 (16)	0.0204 (9)	0.0146 (12)	0.0046 (12)	−0.0043 (11)	0.0025 (10)
Tl2	0.0311 (17)	0.0234 (16)	0.0194 (7)	0.0048 (11)	0.0004 (13)	0.0020 (10)
Tl3	0.0266 (15)	0.0203 (10)	0.0173 (14)	0.0034 (12)	−0.0064 (12)	0.0018 (10)
Tl4	0.0340 (18)	0.0216 (16)	0.0209 (8)	0.0070 (11)	0.0004 (12)	0.0025 (11)

(tdp180_2) top

Crystal data top

Tl₄H₈P₄O₁₆	V = 830.7 (7) Å³
M_r = 1205.5	Z = 2
Triclinic, P1	F(000) = 1040
a = 8.997 (5) Å	D_x = 4.818 Mg m⁻³
b = 14.866 (6) Å	Mo Kα radiation, λ = 0.71073 Å
c = 6.499 (3) Å	µ = 39.14 mm⁻¹
α = 92.03 (3)°	T = 180 K
β = 89.92 (6)°	Irregular, colourless
γ = 107.01 (4)°	× × mm

Data collection top

Imaging plate diffractometer	1504 reflections with 3
phi–rotation scans	R_int = 0.085
Absorption correction: gaussian ?	θ_max = 26.0°, θ_min = 2.4°
T_min = 0.007, T_max = 0.046	h = −10→11
6004 measured reflections	k = −18→18
3017 independent reflections	l = −7→7

Refinement top

Refinement on F²	127 parameters
R[F² > 2σ(F²)] = 0.063	Weighting scheme based on measured s.u.'s w = 1/(σ²(I) + 0.0036I²)
wR(F²) = 0.180	(Δ/σ)_max = 0.240
S = 1.32	Δρ_max = 5.76 e Å⁻³
3017 reflections	Δρ_min = −5.20 e Å⁻³

Crystal data top

Tl₄H₈P₄O₁₆	γ = 107.01 (4)°
M_r = 1205.5	V = 830.7 (7) Å³
Triclinic, P1	Z = 2
a = 8.997 (5) Å	Mo Kα radiation
b = 14.866 (6) Å	µ = 39.14 mm⁻¹
c = 6.499 (3) Å	T = 180 K
α = 92.03 (3)°	× × mm
β = 89.92 (6)°

Data collection top

Imaging plate diffractometer	3017 independent reflections
Absorption correction: gaussian ?	1504 reflections with 3
T_min = 0.007, T_max = 0.046	R_int = 0.085
6004 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.063	127 parameters
wR(F²) = 0.180	(Δ/σ)_max = 0.240
S = 1.32	Δρ_max = 5.76 e Å⁻³
3017 reflections	Δρ_min = −5.20 e Å⁻³

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

	x	y	z	U_iso*/U_eq	Occ. (<1)
Tl1	0.0687 (3)	0.13610 (17)	0.2609 (7)	0.0212 (8)
Tl2	0.4442 (3)	0.3741 (3)	−0.2799 (3)	0.0253 (9)
Tl3	0.5575 (3)	0.11916 (17)	0.2658 (7)	0.0221 (8)
Tl4	0.9466 (3)	0.3691 (3)	0.7635 (2)	0.0257 (9)
P1	0.1723 (17)	0.3758 (10)	0.240 (2)	0.0169 (8)*
O1a	0.286 (4)	0.430 (2)	0.060 (5)	0.024 (3)*
O2a	0.022 (4)	0.314 (2)	0.166 (6)	0.021 (3)*
O3a	0.136 (5)	0.452 (2)	0.385 (5)	0.017 (2)*
O4a	0.270 (4)	0.324 (2)	0.349 (4)	0.014 (2)*
P2	0.2985 (18)	0.1251 (12)	−0.232 (2)	0.0169 (8)*
O1b	0.337 (5)	0.080 (2)	−0.043 (5)	0.024 (3)*
O2b	0.203 (5)	0.194 (2)	−0.161 (5)	0.021 (3)*
O3b	0.187 (4)	0.053 (2)	−0.375 (5)	0.017 (2)*
O4b	0.447 (4)	0.179 (2)	−0.329 (4)	0.014 (2)*
P3	0.6716 (17)	0.3771 (10)	0.231 (2)	0.0169 (8)*
O1c	0.761 (5)	0.420 (2)	0.036 (5)	0.024 (3)*
O2c	0.517 (4)	0.303 (2)	0.180 (5)	0.021 (3)*
O3c	0.650 (4)	0.446 (2)	0.388 (5)	0.017 (2)*
O4c	0.773 (4)	0.319 (2)	0.327 (4)	0.014 (2)*
P4	0.7983 (18)	0.1228 (12)	−0.240 (2)	0.0169 (8)*
O1d	0.842 (5)	0.083 (2)	−0.040 (5)	0.024 (3)*
O2d	0.701 (5)	0.195 (2)	−0.166 (5)	0.021 (3)*
O3d	0.696 (4)	0.050 (2)	−0.384 (5)	0.017 (2)*
O4d	0.952 (4)	0.180 (2)	−0.326 (4)	0.014 (2)*
HO1A	0.23246	0.44715	−0.03001	0.03*	0.5
HO2A	−0.04732	0.34198	0.18302	0.03*	0.5
HO3A	0.20588	0.50418	0.37256	0.03*	0.5
HO4A	0.36346	0.35886	0.35873	0.03*	0.5
HO1B	0.25441	0.05634	0.02401	0.03*	0.5
HO2B	0.18575	0.22340	−0.26384	0.03*	0.5
HO3B	0.22875	0.05188	−0.49210	0.03*	0.5
HO4B	0.51083	0.14666	−0.32895	0.03*	0.5
HO1C	0.70823	0.44918	−0.02838	0.03*	0.5
HO2C	0.45571	0.29929	0.28109	0.03*	0.5
HO3C	0.73635	0.48754	0.41230	0.03*	0.5
HO4C	0.80024	0.28619	0.23263	0.03*	0.5
HO1D	0.76158	0.04427	0.00844	0.03*	0.5
HO2D	0.66079	0.21205	−0.27045	0.03*	0.5
HO3D	0.74747	0.04240	−0.48961	0.03*	0.5
HO4D	1.02242	0.18902	−0.23401	0.03*	0.5

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Tl1	0.0273 (16)	0.0204 (9)	0.0146 (12)	0.0046 (12)	−0.0043 (11)	0.0025 (10)
Tl2	0.0311 (17)	0.0234 (16)	0.0194 (7)	0.0048 (11)	0.0004 (13)	0.0020 (10)
Tl3	0.0266 (15)	0.0203 (10)	0.0173 (14)	0.0034 (12)	−0.0064 (12)	0.0018 (10)
Tl4	0.0340 (18)	0.0216 (16)	0.0209 (8)	0.0070 (11)	0.0004 (12)	0.0025 (11)

Experimental details

	(tdp180_1)	(tdp180_2)
Crystal data
Chemical formula	Tl₄H₈P₄O₁₆	Tl₄H₈P₄O₁₆
M_r	1205.5	1205.5
Crystal system, space group	Triclinic, P1	Triclinic, P1
Temperature (K)	180	180
a, b, c (Å)	8.997 (5), 14.866 (6), 6.499 (3)	8.997 (5), 14.866 (6), 6.499 (3)
α, β, γ (°)	92.03 (3), 89.92 (6), 107.01 (4)	92.03 (3), 89.92 (6), 107.01 (4)
V (Å³)	830.7 (7)	830.7 (7)
Z	2	2
Radiation type	Mo Kα	Mo Kα
µ (mm⁻¹)	39.14	39.14
Crystal size (mm)	× ×	× ×

Data collection
Diffractometer	Imaging plate diffractometer	Imaging plate diffractometer
Absorption correction	Gaussian	Gaussian
T_min, T_max	0.007, 0.046	0.007, 0.046
No. of measured, independent and observed (3) reflections	6004, 3017, 1504	6004, 3017, 1504
R_int	0.085	0.085
(sin θ/λ)_max (Å⁻¹)	0.617	0.617

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.063, 0.180, 1.32	0.063, 0.180, 1.32
No. of reflections	3017	3017
No. of parameters	127	127
No. of restraints	?	?
(Δ/σ)_max	0.240	0.240
Δρ_max, Δρ_min (e Å⁻³)	5.76, −5.20	5.76, −5.20

Computer programs: STOE IPDS, JANA2000 (Petricek et al., 2000), JANA2000 (Petricel et al., 2000).

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Structural study of the low-temperature phase of TlH₂PO₄ at 180 K

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