research papers
The low-temperature phase of TlH2PO4 has been studied by X-ray diffraction. A structural model is proposed with space group P. 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.
Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108768102010066/na0131sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108768102010066/na0131sup2.hkl |
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).
(tdp180_1) top
Crystal data top
Tl4H8P4O16 | V = 830.7 (7) Å3 |
Mr = 1205.5 | Z = 2 |
Triclinic, P1 | F(000) = 1040 |
a = 8.997 (5) Å | Dx = 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 | Rint = 0.085 |
Absorption correction: gaussian ? | θmax = 26.0°, θmin = 2.4° |
Tmin = 0.007, Tmax = 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 | Δρmax = 5.76 e Å−3 |
3017 reflections | Δρmin = −5.20 e Å−3 |
Crystal data top
Tl4H8P4O16 | γ = 107.01 (4)° |
Mr = 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 |
Tmin = 0.007, Tmax = 0.046 | Rint = 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 | Δρmax = 5.76 e Å−3 |
3017 reflections | Δρmin = −5.20 e Å−3 |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
x | y | z | Uiso*/Ueq | ||
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 |
Mr = 1205.5 | Z = 2 |
Triclinic, P1 | F(000) = 1040 |
a = 8.997 (5) Å | Dx = 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 | Rint = 0.085 |
Absorption correction: gaussian ? | θmax = 26.0°, θmin = 2.4° |
Tmin = 0.007, Tmax = 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 | Δρmax = 5.76 e Å−3 |
3017 reflections | Δρmin = −5.20 e Å−3 |
Crystal data top
Tl4H8P4O16 | γ = 107.01 (4)° |
Mr = 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 |
Tmin = 0.007, Tmax = 0.046 | Rint = 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 | Δρmax = 5.76 e Å−3 |
3017 reflections | Δρmin = −5.20 e Å−3 |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
x | y | z | Uiso*/Ueq | 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 |
Mr | 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 |
Tmin, Tmax | 0.007, 0.046 | 0.007, 0.046 |
No. of measured, independent and observed (3) reflections | 6004, 3017, 1504 | 6004, 3017, 1504 |
Rint | 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 |
Δρmax, Δρmin (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).