The structure of, and anisotropic thermal motions in, the red semiconductor tetrahedral layer structure of HgI2 have been studied with neutron powder diffraction as a function of temperature from 10 to 293 K. Average thermal displacement parameters Ueq of the two atoms are comparable in size at 10 K, but Ueq(Hg) increases considerably faster with temperature than Ueq(I), the Hg-I bond being highly non-rigid. The anisotropic displacement tensor U(I) is strongly anisotropic with one term about twice as large as the others, while U(Hg) is nearly isotropic. All displacement tensor elements, except U22(I), increase faster with temperature than harmonic quantum oscillator curves indicating a softening of the isolated-atom potentials at large amplitudes. A lattice dynamical model provides arguments that the anisotropic thermal motions of I are dominated by a soft mode with a wavevector at the [½ ½ 0] boundary of the Brillouin zone consisting essentially of coupled librations of the HgI4 tetrahedra, and by translations of the entire layer. The large vibration amplitudes of Hg suggest weak Hg-I force constants compared with the I-I force constants, allowing Hg to move quite freely inside the tetrahedra. The libration mode induces dynamic deformations of the Hg-I bond with twice its frequency. This provides a mechanism for the anharmonicity and may explain the lightening of the color from red to orange upon cooling at ca 80 K.
Supporting information
For all compounds, program(s) used to refine structure: FULLPROF.
Crystal data top
HgI2 | Z = 2 |
Mr = 454.39 | Dx = 6.450 Mg m−3 |
Tetragonal, P42/nmc | Neutron radiation, λ = 1.371700 Å |
Hall symbol: -P 4ac 2a | T = 10 K |
a = 4.35803 (2) Å | red |
c = 12.30042 (9) Å | cylinder, 52 × 8 mm |
V = 233.62 (1) Å3 | |
Data collection top
Neutron diffractometer | Scan method: step |
Radiation source: continuous spallation neutron source | 2θmin = 4.647°, 2θmax = 164.597°, 2θstep = 0.050° |
Refinement top
Rp = 0.031 | Profile function: 7
(Thompson-Cox-Hastings pseudo-Voigt function convoluted with
axial divergence asymmetry function: J. Appl. Cryst.
(1994). 27, 892) |
Rwp = 0.041 | 28 parameters |
Rexp = 0.025 | 0 restraints |
RBragg = 0.034 | Weighting scheme based on measured s.u.'s |
χ2 = NOT FOUND | |
3200 data points | Background function: FullProf Background function number -4
(cosine Fourier series for background with 12 background
coefficients) |
Excluded region(s): none | |
Crystal data top
HgI2 | V = 233.62 (1) Å3 |
Mr = 454.39 | Z = 2 |
Tetragonal, P42/nmc | Neutron radiation, λ = 1.371700 Å |
a = 4.35803 (2) Å | T = 10 K |
c = 12.30042 (9) Å | cylinder, 52 × 8 mm |
Data collection top
Neutron diffractometer | 2θmin = 4.647°, 2θmax = 164.597°, 2θstep = 0.050° |
Scan method: step | |
Refinement top
Rp = 0.031 | χ2 = NOT FOUND |
Rwp = 0.041 | 3200 data points |
Rexp = 0.025 | 28 parameters |
RBragg = 0.034 | 0 restraints |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
HG1 | 0.25000 | 0.75000 | 0.25000 | 0.00125 (19) | |
I1 | 0.25000 | 0.25000 | 0.39150 (10) | 0.0011 (5) | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
HG1 | 0.00133 (16) | 0.00133 (16) | 0.0011 (2) | 0.00000 | 0.00000 | 0.00000 |
I1 | 0.0024 (5) | 0.0001 (5) | 0.0008 (5) | 0.00000 | 0.00000 | 0.00000 |
Geometric parameters (Å, º) top
Hg1—I1i | 2.7888 (10) | Hg1—I1iii | 2.7888 (10) |
Hg1—I1ii | 2.7888 (10) | I1—Hg1iv | 2.7888 (10) |
Hg1—I1 | 2.7888 (10) | | |
| | | |
I1i—Hg1—I1 | 102.77 (5) | I1i—Hg1—I1iii | 112.92 (3) |
I1ii—Hg1—I1 | 112.92 (3) | I1ii—Hg1—I1iii | 102.77 (5) |
I1iii—Hg1—I1 | 112.92 (3) | Hg1iv—I1—Hg1 | 102.77 (5) |
I1i—Hg1—I1ii | 112.92 (3) | | |
Symmetry codes: (i) −x+1/2, −y+3/2, z; (ii) y+1/2, −x+1, −z+1/2; (iii) −y, x+1/2, −z+1/2; (iv) −x+1/2, −y+1/2, z. |
Crystal data top
HgI2 | Z = 2 |
Mr = 454.39 | Dx = 6.456 Mg m−3 |
Tetragonal, P42/nmc | Neutron radiation, λ = 1.371700 Å |
Hall symbol: -P 4ac 2a | T = 30 K |
a = 4.35808 (4) Å | red |
c = 12.30636 (16) Å | cylinder, 52 × 8 mm |
V = 233.73 (1) Å3 | |
Data collection top
Neutron diffractometer | Scan method: step |
Radiation source: continuous spallation neutron source | 2θmin = 4.645°, 2θmax = 164.595°, 2θstep = 0.050° |
Refinement top
Rp = 0.054 | Profile function: 7
(Thompson-Cox-Hastings pseudo-Voigt function convoluted with
axial divergence asymmetry function: J. Appl. Cryst.
(1994). 27, 892) |
Rwp = 0.064 | 28 parameters |
Rexp = 0.027 | 0 restraints |
RBragg = 0.035 | Weighting scheme based on measured s.u.'s |
χ2 = NOT FOUND | |
3200 data points | Background function: FullProf Background function number -4
(cosine Fourier series for background with 12 background
coefficients) |
Excluded region(s): none | |
Crystal data top
HgI2 | V = 233.73 (1) Å3 |
Mr = 454.39 | Z = 2 |
Tetragonal, P42/nmc | Neutron radiation, λ = 1.371700 Å |
a = 4.35808 (4) Å | T = 30 K |
c = 12.30636 (16) Å | cylinder, 52 × 8 mm |
Data collection top
Neutron diffractometer | 2θmin = 4.645°, 2θmax = 164.595°, 2θstep = 0.050° |
Scan method: step | |
Refinement top
Rp = 0.054 | χ2 = NOT FOUND |
Rwp = 0.064 | 3200 data points |
Rexp = 0.027 | 28 parameters |
RBragg = 0.035 | 0 restraints |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
HG1 | 0.25000 | 0.75000 | 0.25000 | 0.0035 (3) | |
I1 | 0.25000 | 0.25000 | 0.39144 (18) | 0.0027 (8) | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
HG1 | 0.0036 (3) | 0.0036 (3) | 0.0032 (5) | 0.00000 | 0.00000 | 0.00000 |
I1 | 0.0048 (9) | 0.0009 (9) | 0.0025 (8) | 0.00000 | 0.00000 | 0.00000 |
Geometric parameters (Å, º) top
Hg1—I1i | 2.7889 (13) | Hg1—I1iii | 2.7889 (13) |
Hg1—I1ii | 2.7889 (13) | I1—Hg1iv | 2.7889 (13) |
Hg1—I1 | 2.7889 (13) | | |
| | | |
I1i—Hg1—I1 | 102.76 (8) | I1i—Hg1—I1iii | 112.93 (4) |
I1ii—Hg1—I1 | 112.93 (4) | I1ii—Hg1—I1iii | 102.76 (8) |
I1iii—Hg1—I1 | 112.93 (4) | Hg1iv—I1—Hg1 | 102.76 (8) |
I1i—Hg1—I1ii | 112.93 (4) | | |
Symmetry codes: (i) −x+1/2, −y+3/2, z; (ii) y+1/2, −x+1, −z+1/2; (iii) −y, x+1/2, −z+1/2; (iv) −x+1/2, −y+1/2, z. |
Crystal data top
HgI2 | Z = 2 |
Mr = 454.39 | Dx = 6.447 Mg m−3 |
Tetragonal, P42/nmc | Neutron radiation, λ = 1.371700 Å |
Hall symbol: -P 4ac 2a | T = 60 K |
a = 4.35880 (2) Å | red |
c = 12.31850 (11) Å | cylinder, 52 × 8 mm |
V = 234.04 (1) Å3 | |
Data collection top
Neutron diffractometer | Scan method: step |
Radiation source: continuous spallation neutron source | 2θmin = 4.643°, 2θmax = 164.593°, 2θstep = 0.050° |
Refinement top
Rp = 0.027 | Profile function: 7
(Thompson-Cox-Hastings pseudo-Voigt function convoluted with
axial divergence asymmetry function: J. Appl. Cryst.
(1994). 27, 892) |
Rwp = 0.035 | 28 parameters |
Rexp = 0.023 | 0 restraints |
RBragg = 0.039 | Weighting scheme based on measured s.u.'s |
χ2 = NOT FOUND | |
3200 data points | Background function: FullProf Background function number -4
(cosine Fourier series for background with 12 background
coefficients) |
Excluded region(s): none | |
Crystal data top
HgI2 | V = 234.04 (1) Å3 |
Mr = 454.39 | Z = 2 |
Tetragonal, P42/nmc | Neutron radiation, λ = 1.371700 Å |
a = 4.35880 (2) Å | T = 60 K |
c = 12.31850 (11) Å | cylinder, 52 × 8 mm |
Data collection top
Neutron diffractometer | 2θmin = 4.643°, 2θmax = 164.593°, 2θstep = 0.050° |
Scan method: step | |
Refinement top
Rp = 0.027 | χ2 = NOT FOUND |
Rwp = 0.035 | 3200 data points |
Rexp = 0.023 | 28 parameters |
RBragg = 0.039 | 0 restraints |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
HG1 | 0.25000 | 0.75000 | 0.25000 | 0.0071 (2) | |
I1 | 0.25000 | 0.25000 | 0.39120 (12) | 0.0057 (6) | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
HG1 | 0.00713 (19) | 0.00713 (19) | 0.0071 (3) | 0.00000 | 0.00000 | 0.00000 |
I1 | 0.0088 (6) | 0.0040 (6) | 0.0043 (5) | 0.00000 | 0.00000 | 0.00000 |
Geometric parameters (Å, º) top
Hg1—I1i | 2.7884 (10) | Hg1—I1iii | 2.7884 (10) |
Hg1—I1ii | 2.7884 (10) | I1—Hg1iv | 2.7884 (10) |
Hg1—I1 | 2.7884 (10) | | |
| | | |
I1i—Hg1—I1 | 102.81 (6) | I1i—Hg1—I1iii | 112.90 (3) |
I1ii—Hg1—I1 | 112.90 (3) | I1ii—Hg1—I1iii | 102.81 (6) |
I1iii—Hg1—I1 | 112.90 (3) | Hg1iv—I1—Hg1 | 102.81 (6) |
I1i—Hg1—I1ii | 112.90 (3) | | |
Symmetry codes: (i) −x+1/2, −y+3/2, z; (ii) y+1/2, −x+1, −z+1/2; (iii) −y, x+1/2, −z+1/2; (iv) −x+1/2, −y+1/2, z. |
Crystal data top
HgI2 | Z = 2 |
Mr = 454.39 | Dx = 6.433 Mg m−3 |
Tetragonal, P42/nmc | Neutron radiation, λ = 1.371700 Å |
Hall symbol: -P 4ac 2a | T = 100 K |
a = 4.36032 (3) Å | red |
c = 12.33737 (15) Å | cylinder, 52 × 8 mm |
V = 234.56 (1) Å3 | |
Data collection top
Neutron diffractometer | Scan method: step |
Radiation source: continuous spallation neutron source | 2θmin = 4.640°, 2θmax = 164.590°, 2θstep = 0.050° |
Refinement top
Rp = 0.030 | Profile function: 7
(Thompson-Cox-Hastings pseudo-Voigt function convoluted with
axial divergence asymmetry function: J. Appl. Cryst.
(1994). 27, 892) |
Rwp = 0.039 | 28 parameters |
Rexp = 0.023 | 0 restraints |
RBragg = 0.049 | Weighting scheme based on measured s.u.'s |
χ2 = NOT FOUND | |
3200 data points | Background function: FullProf Background function number -4
(cosine Fourier series for background with 12 background
coefficients) |
Excluded region(s): none | |
Crystal data top
HgI2 | V = 234.56 (1) Å3 |
Mr = 454.39 | Z = 2 |
Tetragonal, P42/nmc | Neutron radiation, λ = 1.371700 Å |
a = 4.36032 (3) Å | T = 100 K |
c = 12.33737 (15) Å | cylinder, 52 × 8 mm |
Data collection top
Neutron diffractometer | 2θmin = 4.640°, 2θmax = 164.590°, 2θstep = 0.050° |
Scan method: step | |
Refinement top
Rp = 0.030 | χ2 = NOT FOUND |
Rwp = 0.039 | 3200 data points |
Rexp = 0.023 | 28 parameters |
RBragg = 0.049 | 0 restraints |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
HG1 | 0.25000 | 0.75000 | 0.25000 | 0.0122 (3) | |
I1 | 0.25000 | 0.25000 | 0.39085 (16) | 0.0103 (8) | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
HG1 | 0.0124 (3) | 0.0124 (3) | 0.0120 (5) | 0.00000 | 0.00000 | 0.00000 |
I1 | 0.0157 (9) | 0.0078 (8) | 0.0074 (7) | 0.00000 | 0.00000 | 0.00000 |
Geometric parameters (Å, º) top
Hg1—I1i | 2.7880 (12) | Hg1—I1iii | 2.7880 (12) |
Hg1—I1ii | 2.7880 (12) | I1—Hg1iv | 2.7880 (12) |
Hg1—I1 | 2.7880 (12) | | |
| | | |
I1i—Hg1—I1 | 102.89 (7) | I1i—Hg1—I1iii | 112.86 (4) |
I1ii—Hg1—I1 | 112.86 (4) | I1ii—Hg1—I1iii | 102.89 (7) |
I1iii—Hg1—I1 | 112.86 (4) | Hg1iv—I1—Hg1 | 102.89 (7) |
I1i—Hg1—I1ii | 112.86 (4) | | |
Symmetry codes: (i) −x+1/2, −y+3/2, z; (ii) y+1/2, −x+1, −z+1/2; (iii) −y, x+1/2, −z+1/2; (iv) −x+1/2, −y+1/2, z. |
Crystal data top
HgI2 | Z = 2 |
Mr = 454.39 | Dx = 6.392 Mg m−3 |
Tetragonal, P42/nmc | Neutron radiation, λ = 1.371700 Å |
Hall symbol: -P 4ac 2a | T = 200 K |
a = 4.36525 (7) Å | red |
c = 12.3889 (2) Å | cylinder, 52 × 8 mm |
V = 236.08 (1) Å3 | |
Data collection top
Neutron diffractometer | Scan method: step |
Radiation source: continuous spallation neutron source | 2θmin = 4.629°, 2θmax = 164.579°, 2θstep = 0.050° |
Refinement top
Rp = 0.029 | Profile function: 7
(Thompson-Cox-Hastings pseudo-Voigt function convoluted with
axial divergence asymmetry function: J. Appl. Cryst.
(1994). 27, 892) |
Rwp = 0.037 | 28 parameters |
Rexp = 0.023 | 0 restraints |
RBragg = 0.072 | Weighting scheme based on measured s.u.'s |
χ2 = NOT FOUND | |
3200 data points | Background function: FullProf Background function number -4
(cosine Fourier series for background with 12 background
coefficients) |
Excluded region(s): none | |
Crystal data top
HgI2 | V = 236.08 (1) Å3 |
Mr = 454.39 | Z = 2 |
Tetragonal, P42/nmc | Neutron radiation, λ = 1.371700 Å |
a = 4.36525 (7) Å | T = 200 K |
c = 12.3889 (2) Å | cylinder, 52 × 8 mm |
Data collection top
Neutron diffractometer | 2θmin = 4.629°, 2θmax = 164.579°, 2θstep = 0.050° |
Scan method: step | |
Refinement top
Rp = 0.029 | χ2 = NOT FOUND |
Rwp = 0.037 | 3200 data points |
Rexp = 0.023 | 28 parameters |
RBragg = 0.072 | 0 restraints |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
HG1 | 0.25000 | 0.75000 | 0.25000 | 0.0272 (5) | |
I1 | 0.25000 | 0.25000 | 0.39038 (19) | 0.0218 (12) | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
HG1 | 0.0276 (5) | 0.0276 (5) | 0.0264 (7) | 0.00000 | 0.00000 | 0.00000 |
I1 | 0.0342 (14) | 0.0148 (12) | 0.0164 (11) | 0.00000 | 0.00000 | 0.00000 |
Geometric parameters (Å, º) top
Hg1—I1i | 2.7910 (15) | Hg1—I1iii | 2.7910 (15) |
Hg1—I1ii | 2.7910 (15) | I1—Hg1iv | 2.7910 (15) |
Hg1—I1 | 2.7910 (15) | | |
| | | |
I1i—Hg1—I1 | 102.90 (9) | I1i—Hg1—I1iii | 112.86 (5) |
I1ii—Hg1—I1 | 112.86 (5) | I1ii—Hg1—I1iii | 102.90 (9) |
I1iii—Hg1—I1 | 112.86 (5) | Hg1iv—I1—Hg1 | 102.90 (9) |
I1i—Hg1—I1ii | 112.86 (5) | | |
Symmetry codes: (i) −x+1/2, −y+3/2, z; (ii) y+1/2, −x+1, −z+1/2; (iii) −y, x+1/2, −z+1/2; (iv) −x+1/2, −y+1/2, z. |
Crystal data top
HgI2 | Z = 2 |
Mr = 454.39 | Dx = 6.352 Mg m−3 |
Tetragonal, P42/nmc | Neutron radiation, λ = 1.371700 Å |
Hall symbol: -P 4ac 2a | T = 293 K |
a = 4.3704 (3) Å | red |
c = 12.4368 (10) Å | cylinder, 52 × 8 mm |
V = 237.54 (3) Å3 | |
Data collection top
Neutron diffractometer | Scan method: step |
Radiation source: continuous spallation neutron source | 2θmin = 4.625°, 2θmax = 164.575°, 2θstep = 0.050° |
Refinement top
Rp = 0.063 | Profile function: 7
(Thompson-Cox-Hastings pseudo-Voigt function convoluted with
axial divergence asymmetry function: J. Appl. Cryst.
(1994). 27, 892) |
Rwp = 0.072 | 28 parameters |
Rexp = 0.033 | 0 restraints |
RBragg = 0.086 | Weighting scheme based on measured s.u.'s |
χ2 = NOT FOUND | |
3200 data points | Background function: FullProf Background function number -4
(cosine Fourier series for background with 12 background
coefficients) |
Excluded region(s): none | |
Crystal data top
HgI2 | V = 237.54 (3) Å3 |
Mr = 454.39 | Z = 2 |
Tetragonal, P42/nmc | Neutron radiation, λ = 1.371700 Å |
a = 4.3704 (3) Å | T = 293 K |
c = 12.4368 (10) Å | cylinder, 52 × 8 mm |
Data collection top
Neutron diffractometer | 2θmin = 4.625°, 2θmax = 164.575°, 2θstep = 0.050° |
Scan method: step | |
Refinement top
Rp = 0.063 | χ2 = NOT FOUND |
Rwp = 0.072 | 3200 data points |
Rexp = 0.033 | 28 parameters |
RBragg = 0.086 | 0 restraints |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
HG1 | 0.25000 | 0.75000 | 0.25000 | 0.042 (2) | |
I1 | 0.25000 | 0.25000 | 0.3898 (6) | 0.033 (5) | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
HG1 | 0.0418 (18) | 0.0418 (18) | 0.042 (3) | 0.00000 | 0.00000 | 0.00000 |
I1 | 0.052 (5) | 0.022 (4) | 0.026 (5) | 0.00000 | 0.00000 | 0.00000 |
Geometric parameters (Å, º) top
Hg1—I1i | 2.793 (4) | Hg1—I1iii | 2.793 (4) |
Hg1—I1ii | 2.793 (4) | I1—Hg1iv | 2.793 (4) |
Hg1—I1 | 2.793 (4) | | |
| | | |
I1i—Hg1—I1 | 103.0 (3) | I1i—Hg1—I1iii | 112.81 (13) |
I1ii—Hg1—I1 | 112.81 (13) | I1ii—Hg1—I1iii | 103.0 (3) |
I1iii—Hg1—I1 | 112.81 (13) | Hg1iv—I1—Hg1 | 103.0 (3) |
I1i—Hg1—I1ii | 112.81 (13) | | |
Symmetry codes: (i) −x+1/2, −y+3/2, z; (ii) y+1/2, −x+1, −z+1/2; (iii) −y, x+1/2, −z+1/2; (iv) −x+1/2, −y+1/2, z. |
Experimental details
| (hgi2_n) | (hgi2_n30k) | (hgi2_n60k) | (hgi2_n100k) |
Crystal data |
Chemical formula | HgI2 | HgI2 | HgI2 | HgI2 |
Mr | 454.39 | 454.39 | 454.39 | 454.39 |
Crystal system, space group | Tetragonal, P42/nmc | Tetragonal, P42/nmc | Tetragonal, P42/nmc | Tetragonal, P42/nmc |
Temperature (K) | 10 | 30 | 60 | 100 |
a, c (Å) | 4.35803 (2), 12.30042 (9) | 4.35808 (4), 12.30636 (16) | 4.35880 (2), 12.31850 (11) | 4.36032 (3), 12.33737 (15) |
V (Å3) | 233.62 (1) | 233.73 (1) | 234.04 (1) | 234.56 (1) |
Z | 2 | 2 | 2 | 2 |
Radiation type | Neutron, λ = 1.371700 Å | Neutron, λ = 1.371700 Å | Neutron, λ = 1.371700 Å | Neutron, λ = 1.371700 Å |
Specimen shape, size (mm) | Cylinder, 52 × 8 | Cylinder, 52 × 8 | Cylinder, 52 × 8 | Cylinder, 52 × 8 |
|
Data collection |
Diffractometer | Neutron diffractometer | Neutron diffractometer | Neutron diffractometer | Neutron diffractometer |
Specimen mounting | ? | ? | ? | ? |
Data collection mode | ? | ? | ? | ? |
Scan method | Step | Step | Step | Step |
2θ values (°) | 2θmin = 4.647 2θmax = 164.597 2θstep = 0.050 | 2θmin = 4.645 2θmax = 164.595 2θstep = 0.050 | 2θmin = 4.643 2θmax = 164.593 2θstep = 0.050 | 2θmin = 4.640 2θmax = 164.590 2θstep = 0.050 |
|
Refinement |
R factors and goodness of fit | Rp = 0.031, Rwp = 0.041, Rexp = 0.025, RBragg = 0.034, χ2 = NOT FOUND | Rp = 0.054, Rwp = 0.064, Rexp = 0.027, RBragg = 0.035, χ2 = NOT FOUND | Rp = 0.027, Rwp = 0.035, Rexp = 0.023, RBragg = 0.039, χ2 = NOT FOUND | Rp = 0.030, Rwp = 0.039, Rexp = 0.023, RBragg = 0.049, χ2 = NOT FOUND |
No. of data points | 3200 | 3200 | 3200 | 3200 |
No. of parameters | 28 | 28 | 28 | 28 |
| (hgi2_n200k) | (hgi2_n293k) |
Crystal data |
Chemical formula | HgI2 | HgI2 |
Mr | 454.39 | 454.39 |
Crystal system, space group | Tetragonal, P42/nmc | Tetragonal, P42/nmc |
Temperature (K) | 200 | 293 |
a, c (Å) | 4.36525 (7), 12.3889 (2) | 4.3704 (3), 12.4368 (10) |
V (Å3) | 236.08 (1) | 237.54 (3) |
Z | 2 | 2 |
Radiation type | Neutron, λ = 1.371700 Å | Neutron, λ = 1.371700 Å |
Specimen shape, size (mm) | Cylinder, 52 × 8 | Cylinder, 52 × 8 |
|
Data collection |
Diffractometer | Neutron diffractometer | Neutron diffractometer |
Specimen mounting | ? | ? |
Data collection mode | ? | ? |
Scan method | Step | Step |
2θ values (°) | 2θmin = 4.629 2θmax = 164.579 2θstep = 0.050 | 2θmin = 4.625 2θmax = 164.575 2θstep = 0.050 |
|
Refinement |
R factors and goodness of fit | Rp = 0.029, Rwp = 0.037, Rexp = 0.023, RBragg = 0.072, χ2 = NOT FOUND | Rp = 0.063, Rwp = 0.072, Rexp = 0.033, RBragg = 0.086, χ2 = NOT FOUND |
No. of data points | 3200 | 3200 |
No. of parameters | 28 | 28 |