Valence fluctuations in the incommensurately modulated structure of Calaverite AuTe2
Authors:Schutte, W.J.; de Boer, J.L.
Journal:Acta Cryst. B 44 486-494 (1988)
DOI:https://doi.org/10.1107/S0108768188007001
B-IncStrDB ID: 92ETsjWb Entry date: 2010-11-08 Last revision: 2021-12-30
AuTe2_REFRNCE
Chemical data
Structural Formula Sum: Ag0.14 Au0.86 Te2 [ Help ]
Formula weight: 439.7 Da [ Help ]
Mineral Name: Calaverite [ Help ]
Crystallographic data and experimental details
a: 7.182(1) Å [ Help ]
b: 4.402(1) Å [ Help ]
c: 5.056(1) Å [ Help ]
α: 90.0 ° [ Help ]
β: 89.99(2) ° [ Help ]
γ: 90.0 ° [ Help ]
Volume: 159.85(5) Å3 [ Help ]
Z: 2 [ Help ]
Cell measurement temperature: 100.0 K [ Help ]
μ: 58.026 mm-1 [ Help ]
Crystal system: monoclinic [ Help ]
Space group name (H-M): C 2/m [ Help ]
Space group name (Hall): -C 2y [ Help ]
Symmetry operations of the space group: (Show/hide table) [ Help ]
| Operation code | Operation in algebraic form |
|---|---|
| 1 | x,y,z |
| 2 | -x,y,-z |
| 3 | -x,-y,-z |
| 4 | x,-y,z |
| 5 | 1/2+x,1/2+y,z |
| 6 | 1/2-x,1/2+y,-z |
| 7 | 1/2-x,1/2-y,-z |
| 8 | 1/2+x,1/2-y,z |
Refinement details
Refinement remarks: WARNING: The published thermal displacement parameters have been converted to U,s. The calculated standard uncertainties (s.u.) have been based uniquely on the published ones without considering the s.u. of any other quantity involved in such conversion. [ Help ]
Nb. of observed reflections: 707 [ Help ]
R(obs): 0.087 [ Help ]
Structural Information
Average Structure: (Show/hide table) [ Help ]
| Atom site label | Atom symbol | Symmetry multiplicity | Occupancy | x | y | z | Uiso/equiv | ADP type |
|---|---|---|---|---|---|---|---|---|
| Au | Au | 2 | 0.86(4) | 0.0 | 0.0 | 0.0 | ? | Uani |
| Ag | Ag | 2 | 0.14(4) | 0.0 | 0.0 | 0.0 | ? | Uani |
| Te | Te | 4 | 1.0 | 0.689(2) | 0.0 | 0.2888(3) | ? | Uani |
ADP components: (Show/hide table) [ Help ]
| Atom site label | Atom site symbol | U11 | U22 | U33 | U12 | U13 | U23 |
|---|---|---|---|---|---|---|---|
| Au | Au | 0.0037(3) | 0.0066(4) | 0.0048(4) | 0.0 | 0.00092(18) | 0.0 |
| Ag | Ag | 0.0037(3) | 0.0066(4) | 0.0048(4) | 0.0 | 0.00092(18) | 0.0 |
| Te | Te | 0.0042(5) | 0.105(3) | 0.0056(6) | 0.0 | 0.0013(4) | 0.0 |
AuTe_MOD
Chemical data
Structural Formula Sum: Ag0.086 Au0.914 Te2 [ Help ]
Formula weight: 444.5 Da [ Help ]
Mineral Name: Calaverite [ Help ]
Crystallographic data and experimental details
Modulation dimension: 1 [ Help ]
a: 7.182(1) Å [ Help ]
b: 4.402(1) Å [ Help ]
c: 5.056(1) Å [ Help ]
α: 90.0 ° [ Help ]
β: 89.99(2) ° [ Help ]
γ: 90.0 ° [ Help ]
Volume: 159.85(5) Å3 [ Help ]
Z: 2 [ Help ]
μ: 60.171 mm-1 [ Help ]
Cell measurement temperature: 100.0 K [ Help ]
Crystal system: monoclinic [ Help ]
Superspace group name (WJJ): P:C 2/m:-1 s [ Help ]
Superspace group name: C2/m(α0γ)0s [ Help ]
Space group name (H-M): C 2/m [ Help ]
Symmetry operations of the superspace group: (Show/hide table) [ Help ]
| Operation code | Operation in algebraic form |
|---|---|
| 1 | x1,x2,x3,x4 |
| 2 | -x1,x2,-x3,1/2-x4 |
| 3 | -x1,-x2,-x3,-x4 |
| 4 | x1,-x2,x3,1/2+x4 |
| 5 | 1/2+x1,1/2+x2,x3,x4 |
| 6 | 1/2-x1,1/2+x2,-x3,1/2-x4 |
| 7 | 1/2-x1,1/2-x2,-x3,-x4 |
| 8 | 1/2+x1,1/2-x2,x3,1/2+x4 |
Measured independent wave vectors: (Show/hide table) [ Help ]
| Wave vector id | q_x | q_y | q_z |
|---|---|---|---|
| 1 | -0.4078(15) | 0.0 | 0.4483(6) |
Refinement details
Refinement remarks: WARNING: The published thermal displacement parameters have been converted to U,s. The calculated standard uncertainties (s.u.) have been based uniquely on the published ones without considering the s.u. of any other quantity involved in such conversion. [ Help ]
Modulation functions description: Displacive modulation:Fourier series. Up to 3rd-order harmonics. Occupational modulation:Fourier series. 2nd-order harmonics. [ Help ]
Structure factors calc. details: Gaussian integration [ Help ]
Nb. of observed reflections: 2002 [ Help ]
R(obs): 0.043 [ Help ]
Structural Information
Average Structure: (Show/hide table) [ Help ]
| Atom site label | Atom symbol | Symmetry multiplicity | Occupancy | x | y | z | Uiso/equiv | ADP type |
|---|---|---|---|---|---|---|---|---|
| Au | Au | 2 | 0.914(4) | 0.0 | 0.0 | 0.0 | ? | Uani |
| Ag | Ag | 2 | 0.086(4) | 0.0 | 0.0 | 0.0 | ? | Uani |
| Te | Te | 4 | 1.0 | 0.68891(5) | 0.0 | 0.28839(7) | ? | Uani |
Fourier Wave Vectors (explicit: q_x,q_y,q_z or coefficients: q_1,q_2,...): (Show/hide table) [ Help ]
| Wave vector code | q_x | q_y | q_z |
|---|---|---|---|
| 1 | -0.4078 | 0.0 | 0.4483 |
| 2 | -0.8156 | 0.0 | 0.8966 |
| 3 | -1.2234 | 0.0 | 1.3449 |
Definition of the displacive (translational) Fourier series: (Show/hide table) [ Help ]
| Modulation code | Atom site label | Displacement axis | Wave vector code |
|---|---|---|---|
| Aux2 | Au | x | 2 |
| Auy1 | Au | y | 1 |
| Auy3 | Au | y | 3 |
| Auz2 | Au | z | 2 |
| Agx2 | Ag | x | 2 |
| Agy1 | Ag | y | 1 |
| Agy3 | Ag | y | 3 |
| Agz2 | Ag | z | 2 |
| Tex2 | Te | x | 2 |
| Tey1 | Te | y | 1 |
| Tey3 | Te | y | 3 |
| Tez2 | Te | z | 2 |
Displacive (translational) Fourier coefficients: (Show/hide table) [ Help ]
| Modulation code | Cosine coefficient | Sine coefficient |
|---|---|---|
| Aux2 | 0.0 | -0.0001(1) |
| Auy1 | 0.0104(1) | 0.0 |
| Auy3 | -0.0051(2) | 0.0 |
| Auz2 | 0.0 | -0.0017(1) |
| Agx2 | 0.0 | -0.0001(1) |
| Agy1 | 0.0104(1) | 0.0 |
| Agy3 | -0.0051(2) | 0.0 |
| Agz2 | 0.0 | -0.0017(1) |
| Tex2 | 0.001(1) | 0.0012(1) |
| Tey1 | -0.0024(2) | 0.0821(1) |
| Tey3 | 0.0065(2) | 0.0016(2) |
| Tez2 | 0.0039(1) | 0.006(1) |
Definition of the occupation Fourier series: (Show/hide table) [ Help ]
| Modulation code | Atom site label | Wave vector code |
|---|---|---|
| Auo2 | Au | 2 |
Occupation Fourier coefficients: (Show/hide table) [ Help ]
| Modulation code | Cosine coefficient | Sine coefficient |
|---|---|---|
| Auo2 | -0.089(4) | 0.0 |
ADP components: (Show/hide table) [ Help ]
| Atom site label | Atom site symbol | U11 | U22 | U33 | U12 | U13 | U23 |
|---|---|---|---|---|---|---|---|
| Au | Au | 0.00381(10) | 0.0054(10) | 0.005(10) | 0.0 | 0.00098(7) | 0.0 |
| Ag | Ag | 0.00381(10) | 0.0054(10) | 0.005(10) | 0.0 | 0.00098(7) | 0.0 |
| Te | Te | 0.00457(13) | 0.0041(2) | 0.00492(13) | 0.0 | 0.00072(9) | 0.0 |