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The crystal and local atomic structure of monoclinic ReO2 (α-ReO2) under hydrostatic pressure up to 1.2 GPa was investigated for the first time using both X-ray absorption spectroscopy and high-resolution synchrotron X-ray powder diffraction and a home-built B4C anvil pressure cell developed for this purpose. Extended X-ray absorption fine-structure (EXAFS) data analysis at pressures from ambient up to 1.2 GPa indicates that there are two distinct Re—Re distances and a distorted ReO6 octahedron in the α-ReO2 structure. X-ray diffraction analysis at ambient pressure revealed an unambiguous solution for the crystal structure of the α-phase, demonstrating a modulation of the Re—Re distances. The relatively small portion of the diffraction pattern accessed in the pressure-dependent measurements does not allow for a detailed study of the crystal structure of α-ReO2 under pressure. Nonetheless, a shift and reduction in the (011) Bragg peak intensity between 0.4 and 1.2 GPa is observed, with correlation to a decrease in Re—Re distance modulation, as confirmed by EXAFS analysis in the same pressure range. This behavior reveals that α-ReO2 is a possible inner pressure gauge for future experiments up to 1.2 GPa.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0909049508036029/wa5006sup1.cif
Contains datablocks REO2_publ, REO2_overall, REO2_phase_1, REO2_phase_2, REO2_phase_3, REO2_p_01

Computing details top

Figures top
[Figure 1]
[Figure 2]
[Figure 3]
[Figure 4]
[Figure 5]
[Figure 6]
[Figure 7]
[Figure 8]
[Figure 9]
[Figure 10]
(REO2_phase_1) top
Crystal data top
O2Reβ = 120.2721 (18)°
Mr = 218.21V = 129.17 (1) Å3
Monoclinic, P21/cZ = 4
a = 5.61113 (15) Å? radiation, λ = 1.239998 Å
b = 4.80456 (9) Å?, ? × ? × ? mm
c = 5.54783 (17) Å
Data collection top
2θmin = 13.998°, 2θmax = 99.988°, 2θstep = 0.01°
Refinement top
Least-squares matrix: full8600 data points
Rp = 0.092Profile function: CW Profile function number 4 with 21 terms Pseudovoigt profile coefficients as parameterized in P. Thompson, D.E. Cox & J.B. Hastings (1987). J. Appl. Cryst.,20,79-83. Asymmetry correction of L.W. Finger, D.E. Cox & A. P. Jephcoat (1994). J. Appl. Cryst.,27,892-900. Microstrain broadening by P.W. Stephens, (1999). J. Appl. Cryst.,32,281-289. #1(GU) = 0.000 #2(GV) = 0.000 #3(GW) = 0.000 #4(GP) = 0.000 #5(LX) = 2.858 #6(ptec) = 0.00 #7(trns) = 0.00 #8(shft) = 0.3326 #9(sfec) = 0.00 #10(S/L) = 0.0063 #11(H/L) = 0.0063 #12(eta) = 0.4445 #13(S400 ) = 2.2E+00 #14(S040 ) = 6.8E+00 #15(S004 ) = 7.4E+00 #16(S220 ) = 3.5E-01 #17(S202 ) = 5.9E+00 #18(S022 ) = -3.1E+00 #19(S301 ) = 4.4E+00 #20(S103 ) = 5.9E+00 #21(S121 ) = -3.3E-01 Peak tails are ignored where the intensity is below 0.0010 times the peak Aniso. broadening axis 0.0 0.0 1.0, CW Profile function number 4 with 16 terms Pseudovoigt profile coefficients as parameterized in P. Thompson, D.E. Cox & J.B. Hastings (1987). J. Appl. Cryst.,20,79-83. Asymmetry correction of L.W. Finger, D.E. Cox & A. P. Jephcoat (1994). J. Appl. Cryst.,27,892-900. Microstrain broadening by P.W. Stephens, (1999). J. Appl. Cryst.,32,281-289. #1(GU) = 0.000 #2(GV) = 0.000 #3(GW) = 0.000 #4(GP) = 0.000 #5(LX) = 2.680 #6(ptec) = 0.00 #7(trns) = 0.00 #8(shft) = 0.3326 #9(sfec) = 0.00 #10(S/L) = 0.0063 #11(H/L) = 0.0063 #12(eta) = 0.9810 #13(S400 ) = 4.1E-02 #14(S004 ) = 3.0E-05 #15(S220 ) = -2.6E-02 #16(S202 ) = 6.3E-01 Peak tails are ignored where the intensity is below 0.0010 times the peak Aniso. broadening axis 0.0 0.0 1.0, CW Profile function number 4 with 18 terms Pseudovoigt profile coefficients as parameterized in P. Thompson, D.E. Cox & J.B. Hastings (1987). J. Appl. Cryst.,20,79-83. Asymmetry correction of L.W. Finger, D.E. Cox & A. P. Jephcoat (1994). J. Appl. Cryst.,27,892-900. Microstrain broadening by P.W. Stephens, (1999). J. Appl. Cryst.,32,281-289. #1(GU) = 0.000 #2(GV) = 0.000 #3(GW) = 0.000 #4(GP) = 0.000 #5(LX) = 10.115 #6(ptec) = 0.00 #7(trns) = 0.00 #8(shft) = 0.3326 #9(sfec) = 0.00 #10(S/L) = 0.0063 #11(H/L) = 0.0063 #12(eta) = 0.6973 #13(S400 ) = 7.4E-01 #14(S040 ) = 2.2E+00 #15(S004 ) = 3.8E+00 #16(S220 ) = 7.7E-01 #17(S202 ) = -6.7E-01 #18(S022 ) = 5.0E-01 Peak tails are ignored where the intensity is below 0.0010 times the peak Aniso. broadening axis 0.0 0.0 1.0
Rwp = 0.12157 parameters
Rexp = 0.0910 restraints
R(F2) = 0.05927(Δ/σ)max = 0.05
χ2 = 1.769Background function: GSAS Background function number 1 with 14 terms. Shifted Chebyshev function of 1st kind 1: 43.6672 2: -14.9861 3: 2.15605 4: -1.46007 5: -0.693433 6: 2.03766 7: -3.19664 8: 3.10886 9: -0.434656 10: -1.86818 11: 4.98375 12: -3.92371 13: 1.06103 14: -0.269726
Crystal data top
O2Reβ = 120.2721 (18)°
Mr = 218.21V = 129.17 (1) Å3
Monoclinic, P21/cZ = 4
a = 5.61113 (15) Å? radiation, λ = 1.239998 Å
b = 4.80456 (9) Å?, ? × ? × ? mm
c = 5.54783 (17) Å
Data collection top
2θmin = 13.998°, 2θmax = 99.988°, 2θstep = 0.01°
Refinement top
Rp = 0.092χ2 = 1.769
Rwp = 0.1218600 data points
Rexp = 0.09157 parameters
R(F2) = 0.059270 restraints
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Re10.2379 (2)0.0026 (15)0.0067 (3)0.01831 (11)*
O10.112 (5)0.200 (5)0.227 (4)0.01831 (11)*
O20.387 (5)0.709 (5)0.293 (4)0.01831 (11)*
(REO2_phase_2) top
Crystal data top
O3ReV = 105.29 (1) Å3
Mr = 234.20Z = 2
Tetragonal, P4/mbm? radiation, λ = 1.239998 Å
a = 5.30107 (11) Å?, ? × ? × ? mm
c = 3.74690 (16) Å
Data collection top
2θmin = 13.998°, 2θmax = 99.988°, 2θstep = 0.01°
Refinement top
Least-squares matrix: full8600 data points
Rp = 0.092Profile function: CW Profile function number 4 with 21 terms Pseudovoigt profile coefficients as parameterized in P. Thompson, D.E. Cox & J.B. Hastings (1987). J. Appl. Cryst.,20,79-83. Asymmetry correction of L.W. Finger, D.E. Cox & A. P. Jephcoat (1994). J. Appl. Cryst.,27,892-900. Microstrain broadening by P.W. Stephens, (1999). J. Appl. Cryst.,32,281-289. #1(GU) = 0.000 #2(GV) = 0.000 #3(GW) = 0.000 #4(GP) = 0.000 #5(LX) = 2.858 #6(ptec) = 0.00 #7(trns) = 0.00 #8(shft) = 0.3326 #9(sfec) = 0.00 #10(S/L) = 0.0063 #11(H/L) = 0.0063 #12(eta) = 0.4445 #13(S400 ) = 2.2E+00 #14(S040 ) = 6.8E+00 #15(S004 ) = 7.4E+00 #16(S220 ) = 3.5E-01 #17(S202 ) = 5.9E+00 #18(S022 ) = -3.1E+00 #19(S301 ) = 4.4E+00 #20(S103 ) = 5.9E+00 #21(S121 ) = -3.3E-01 Peak tails are ignored where the intensity is below 0.0010 times the peak Aniso. broadening axis 0.0 0.0 1.0, CW Profile function number 4 with 16 terms Pseudovoigt profile coefficients as parameterized in P. Thompson, D.E. Cox & J.B. Hastings (1987). J. Appl. Cryst.,20,79-83. Asymmetry correction of L.W. Finger, D.E. Cox & A. P. Jephcoat (1994). J. Appl. Cryst.,27,892-900. Microstrain broadening by P.W. Stephens, (1999). J. Appl. Cryst.,32,281-289. #1(GU) = 0.000 #2(GV) = 0.000 #3(GW) = 0.000 #4(GP) = 0.000 #5(LX) = 2.680 #6(ptec) = 0.00 #7(trns) = 0.00 #8(shft) = 0.3326 #9(sfec) = 0.00 #10(S/L) = 0.0063 #11(H/L) = 0.0063 #12(eta) = 0.9810 #13(S400 ) = 4.1E-02 #14(S004 ) = 3.0E-05 #15(S220 ) = -2.6E-02 #16(S202 ) = 6.3E-01 Peak tails are ignored where the intensity is below 0.0010 times the peak Aniso. broadening axis 0.0 0.0 1.0, CW Profile function number 4 with 18 terms Pseudovoigt profile coefficients as parameterized in P. Thompson, D.E. Cox & J.B. Hastings (1987). J. Appl. Cryst.,20,79-83. Asymmetry correction of L.W. Finger, D.E. Cox & A. P. Jephcoat (1994). J. Appl. Cryst.,27,892-900. Microstrain broadening by P.W. Stephens, (1999). J. Appl. Cryst.,32,281-289. #1(GU) = 0.000 #2(GV) = 0.000 #3(GW) = 0.000 #4(GP) = 0.000 #5(LX) = 10.115 #6(ptec) = 0.00 #7(trns) = 0.00 #8(shft) = 0.3326 #9(sfec) = 0.00 #10(S/L) = 0.0063 #11(H/L) = 0.0063 #12(eta) = 0.6973 #13(S400 ) = 7.4E-01 #14(S040 ) = 2.2E+00 #15(S004 ) = 3.8E+00 #16(S220 ) = 7.7E-01 #17(S202 ) = -6.7E-01 #18(S022 ) = 5.0E-01 Peak tails are ignored where the intensity is below 0.0010 times the peak Aniso. broadening axis 0.0 0.0 1.0
Rwp = 0.12157 parameters
Rexp = 0.0910 restraints
R(F2) = 0.05927(Δ/σ)max = 0.05
χ2 = 1.769Background function: GSAS Background function number 1 with 14 terms. Shifted Chebyshev function of 1st kind 1: 43.6672 2: -14.9861 3: 2.15605 4: -1.46007 5: -0.693433 6: 2.03766 7: -3.19664 8: 3.10886 9: -0.434656 10: -1.86818 11: 4.98375 12: -3.92371 13: 1.06103 14: -0.269726
Crystal data top
O3ReV = 105.29 (1) Å3
Mr = 234.20Z = 2
Tetragonal, P4/mbm? radiation, λ = 1.239998 Å
a = 5.30107 (11) Å?, ? × ? × ? mm
c = 3.74690 (16) Å
Data collection top
2θmin = 13.998°, 2θmax = 99.988°, 2θstep = 0.01°
Refinement top
Rp = 0.092χ2 = 1.769
Rwp = 0.1218600 data points
Rexp = 0.09157 parameters
R(F2) = 0.059270 restraints
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Re10.00.00.50.0175 (11)*
O10.00.00.00.0175 (11)*
O20.102 (9)0.602 (9)0.50.0175 (11)*
(REO2_phase_3) top
Crystal data top
O2Rec = 4.6129 (2) Å
Mr = 218.21V = 124.83 (1) Å3
Orthorhombic, PbcnZ = 4
a = 4.8040 (2) Å? radiation, λ = 1.239998 Å
b = 5.6332 (4) Å?, ? × ? × ? mm
Data collection top
2θmin = 13.998°, 2θmax = 99.988°, 2θstep = 0.01°
Refinement top
Least-squares matrix: full8600 data points
Rp = 0.092Profile function: CW Profile function number 4 with 21 terms Pseudovoigt profile coefficients as parameterized in P. Thompson, D.E. Cox & J.B. Hastings (1987). J. Appl. Cryst.,20,79-83. Asymmetry correction of L.W. Finger, D.E. Cox & A. P. Jephcoat (1994). J. Appl. Cryst.,27,892-900. Microstrain broadening by P.W. Stephens, (1999). J. Appl. Cryst.,32,281-289. #1(GU) = 0.000 #2(GV) = 0.000 #3(GW) = 0.000 #4(GP) = 0.000 #5(LX) = 2.858 #6(ptec) = 0.00 #7(trns) = 0.00 #8(shft) = 0.3326 #9(sfec) = 0.00 #10(S/L) = 0.0063 #11(H/L) = 0.0063 #12(eta) = 0.4445 #13(S400 ) = 2.2E+00 #14(S040 ) = 6.8E+00 #15(S004 ) = 7.4E+00 #16(S220 ) = 3.5E-01 #17(S202 ) = 5.9E+00 #18(S022 ) = -3.1E+00 #19(S301 ) = 4.4E+00 #20(S103 ) = 5.9E+00 #21(S121 ) = -3.3E-01 Peak tails are ignored where the intensity is below 0.0010 times the peak Aniso. broadening axis 0.0 0.0 1.0, CW Profile function number 4 with 16 terms Pseudovoigt profile coefficients as parameterized in P. Thompson, D.E. Cox & J.B. Hastings (1987). J. Appl. Cryst.,20,79-83. Asymmetry correction of L.W. Finger, D.E. Cox & A. P. Jephcoat (1994). J. Appl. Cryst.,27,892-900. Microstrain broadening by P.W. Stephens, (1999). J. Appl. Cryst.,32,281-289. #1(GU) = 0.000 #2(GV) = 0.000 #3(GW) = 0.000 #4(GP) = 0.000 #5(LX) = 2.680 #6(ptec) = 0.00 #7(trns) = 0.00 #8(shft) = 0.3326 #9(sfec) = 0.00 #10(S/L) = 0.0063 #11(H/L) = 0.0063 #12(eta) = 0.9810 #13(S400 ) = 4.1E-02 #14(S004 ) = 3.0E-05 #15(S220 ) = -2.6E-02 #16(S202 ) = 6.3E-01 Peak tails are ignored where the intensity is below 0.0010 times the peak Aniso. broadening axis 0.0 0.0 1.0, CW Profile function number 4 with 18 terms Pseudovoigt profile coefficients as parameterized in P. Thompson, D.E. Cox & J.B. Hastings (1987). J. Appl. Cryst.,20,79-83. Asymmetry correction of L.W. Finger, D.E. Cox & A. P. Jephcoat (1994). J. Appl. Cryst.,27,892-900. Microstrain broadening by P.W. Stephens, (1999). J. Appl. Cryst.,32,281-289. #1(GU) = 0.000 #2(GV) = 0.000 #3(GW) = 0.000 #4(GP) = 0.000 #5(LX) = 10.115 #6(ptec) = 0.00 #7(trns) = 0.00 #8(shft) = 0.3326 #9(sfec) = 0.00 #10(S/L) = 0.0063 #11(H/L) = 0.0063 #12(eta) = 0.6973 #13(S400 ) = 7.4E-01 #14(S040 ) = 2.2E+00 #15(S004 ) = 3.8E+00 #16(S220 ) = 7.7E-01 #17(S202 ) = -6.7E-01 #18(S022 ) = 5.0E-01 Peak tails are ignored where the intensity is below 0.0010 times the peak Aniso. broadening axis 0.0 0.0 1.0
Rwp = 0.12157 parameters
Rexp = 0.0910 restraints
R(F2) = 0.05927(Δ/σ)max = 0.05
χ2 = 1.769Background function: GSAS Background function number 1 with 14 terms. Shifted Chebyshev function of 1st kind 1: 43.6672 2: -14.9861 3: 2.15605 4: -1.46007 5: -0.693433 6: 2.03766 7: -3.19664 8: 3.10886 9: -0.434656 10: -1.86818 11: 4.98375 12: -3.92371 13: 1.06103 14: -0.269726
Crystal data top
O2Rec = 4.6129 (2) Å
Mr = 218.21V = 124.83 (1) Å3
Orthorhombic, PbcnZ = 4
a = 4.8040 (2) Å? radiation, λ = 1.239998 Å
b = 5.6332 (4) Å?, ? × ? × ? mm
Data collection top
2θmin = 13.998°, 2θmax = 99.988°, 2θstep = 0.01°
Refinement top
Rp = 0.092χ2 = 1.769
Rwp = 0.1218600 data points
Rexp = 0.09157 parameters
R(F2) = 0.059270 restraints
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Re10.00.1089 (4)0.250.0072 (3)*
O10.239 (4)0.359 (8)0.109 (4)0.0072 (3)*

Experimental details

(REO2_phase_1)(REO2_phase_2)(REO2_phase_3)
Crystal data
Chemical formulaO2ReO3ReO2Re
Mr218.21234.20218.21
Crystal system, space groupMonoclinic, P21/cTetragonal, P4/mbmOrthorhombic, Pbcn
Temperature (K)???
a, b, c (Å)5.61113 (15), 4.80456 (9), 5.54783 (17)5.30107 (11), 5.30107, 3.74690 (16)4.8040 (2), 5.6332 (4), 4.6129 (2)
α, β, γ (°)90, 120.2721 (18), 9090, 90, 9090, 90, 90
V3)129.17 (1)105.29 (1)124.83 (1)
Z424
Radiation type?, λ = 1.239998 Å?, λ = 1.239998 Å?, λ = 1.239998 Å
Specimen shape, size (mm)?, ? × ? × ??, ? × ? × ??, ? × ? × ?
Data collection
Diffractometer???
Specimen mounting???
Data collection mode???
Scan method???
2θ values (°)2θmin = 13.998 2θmax = 99.988 2θstep = 0.012θmin = 13.998 2θmax = 99.988 2θstep = 0.012θmin = 13.998 2θmax = 99.988 2θstep = 0.01
Refinement
R factors and goodness of fitRp = 0.092, Rwp = 0.121, Rexp = 0.091, R(F2) = 0.05927, χ2 = 1.769Rp = 0.092, Rwp = 0.121, Rexp = 0.091, R(F2) = 0.05927, χ2 = 1.769Rp = 0.092, Rwp = 0.121, Rexp = 0.091, R(F2) = 0.05927, χ2 = 1.769
No. of data points860086008600
No. of parameters575757

Computer programs: GSAS.

 

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