Modulated structure of NiTa2Se7 in its incommensurate charge-density-wave state at 16 K
Authors:Spijkerman, A.; Meetsma, A.; de Boer, J.L.; Gao, Y.; van Smaalen, S.
Journal:Phys. Rev. B 52 3892-3899 (1995)
DOI:https://doi.org/10.1103/PhysRevB.52.3892
B-IncStrDB ID: 732EPzzH0 Entry date: 2010-11-08 Last revision: 2021-12-30
NiTa
Chemical data
Structural Formula Sum: Ni1 Se7 Ta2 [ Help ]
Formula weight: 973.3 Da [ Help ]
Crystallographic data and experimental details
a: 13.873(16) Å [ Help ]
b: 3.490(6) Å [ Help ]
c: 18.624(22) Å [ Help ]
α: 90 ° [ Help ]
β: 109.003(5) ° [ Help ]
γ: 90 ° [ Help ]
Volume: 853(2) Å3 [ Help ]
Z: 4 [ Help ]
μ: 57.586 mm-1 [ Help ]
Cell measurement temperature: 16 K [ Help ]
Crystal system: monoclinic [ Help ]
Superspace group name (ITC): C 2/m (0 β 0) s -1 [ Help ]
Superspace group name: C2/m(0β0)s0 [ 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 |
Space group name (H-M): C 1 2/m 1 [ Help ]
Modulation dimension: 1 [ Help ]
Measured independent wave vectors: (Show/hide table) [ Help ]
| Wave vector id | q_x | q_y | q_z |
|---|---|---|---|
| 1 | 0 | 0.483 | 0 |
Refinement details
Refinement remarks: Only main reflections and 1st-order satellites were used in the refinement. WARNING: The published displacement parameters have been converted to relative units. 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. 1st-order harmonics. [ Help ]
Nb. of observed reflections: 515 [ Help ]
R(obs): 0.092 [ Help ]
wR(all): 0.141 [ Help ]
Structural Information
Average Structure: (Show/hide table) [ Help ]
| Atom site label | Atom symbol | Symmetry multiplicity | Occupancy | x | y | z | Uiso/equiv | ADP type |
|---|---|---|---|---|---|---|---|---|
| Ta1 | Ta | 4 | 1 | 0.1503(2) | 0 | 0.3988(2) | ? | Uani |
| Ta2 | Ta | 4 | 1 | 0.2291(2) | 0 | 0.0898(2) | ? | Uani |
| Ni | Ni | 4 | 1 | 0.1905(5) | 0.5 | 0.2097(4) | ? | Uani |
| Se1 | Se | 4 | 1 | 0.3663(6) | 0 | 0.0125(4) | ? | Uani |
| Se2 | Se | 4 | 1 | 0.0602(4) | 0.5 | 0.2945(3) | ? | Uani |
| Se3 | Se | 4 | 1 | 0.0820(5) | 0 | 0.1365(3) | ? | Uani |
| Se4 | Se | 4 | 1 | 0.3450(5) | 0.5 | 0.1742(4) | ? | Uani |
| Se5 | Se | 4 | 1 | 0.0184(5) | 0.5 | 0.4172(3) | ? | Uani |
| Se6 | Se | 4 | 1 | 0.3008(5) | 0.5 | 0.4461(3) | ? | Uani |
| Se7 | Se | 4 | 1 | 0.2584(5) | 0 | 0.3002(3) | ? | 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 | 0.483 | 0 |
Definition of the displacive (translational) Fourier series: (Show/hide table) [ Help ]
| Modulation code | Atom site label | Displacement axis | Wave vector code |
|---|---|---|---|
| Ta1x1 | Ta1 | x | 1 |
| Ta1y1 | Ta1 | y | 1 |
| Ta1z1 | Ta1 | z | 1 |
| Ta2x1 | Ta2 | x | 1 |
| Ta2y1 | Ta2 | y | 1 |
| Ta2z1 | Ta2 | z | 1 |
| Nix1 | Ni | x | 1 |
| Niy1 | Ni | y | 1 |
| Niz1 | Ni | z | 1 |
| Se1x1 | Se1 | x | 1 |
| Se1y1 | Se1 | y | 1 |
| Se1z1 | Se1 | z | 1 |
| Se2x1 | Se2 | x | 1 |
| Se2y1 | Se2 | y | 1 |
| Se2z1 | Se2 | z | 1 |
| Se3x1 | Se3 | x | 1 |
| Se3y1 | Se3 | y | 1 |
| Se3z1 | Se3 | z | 1 |
| Se4x1 | Se4 | x | 1 |
| Se4y1 | Se4 | y | 1 |
| Se4z1 | Se4 | z | 1 |
| Se5x1 | Se5 | x | 1 |
| Se5y1 | Se5 | y | 1 |
| Se5z1 | Se5 | z | 1 |
| Se6x1 | Se6 | x | 1 |
| Se6y1 | Se6 | y | 1 |
| Se6z1 | Se6 | z | 1 |
| Se7x1 | Se7 | x | 1 |
| Se7y1 | Se7 | y | 1 |
| Se7z1 | Se7 | z | 1 |
Displacive (translational) Fourier coefficients: (Show/hide table) [ Help ]
| Modulation code | Cosine coefficient | Sine coefficient |
|---|---|---|
| Ta1x1 | 0 | -0.0001(1) |
| Ta1y1 | 0.0080(3) | 0 |
| Ta1z1 | 0 | -0.0002(1) |
| Ta2x1 | 0 | -0.0017(1) |
| Ta2y1 | -0.006(3) | 0 |
| Ta2z1 | 0 | -0.0012(1) |
| Nix1 | 0 | -0.0038(4) |
| Niy1 | -0.0020(9) | 0 |
| Niz1 | 0 | 0.0032(3) |
| Se1x1 | 0 | 0.0005(2) |
| Se1y1 | 0.0037(9) | 0 |
| Se1z1 | 0 | -0.0001(2) |
| Se2x1 | 0 | 0.0077(4) |
| Se2y1 | -0.0011(9) | 0 |
| Se2z1 | 0 | -0.0040(2) |
| Se3x1 | 0 | -0.0002(3) |
| Se3y1 | -0.0092(9) | 0 |
| Se3z1 | 0 | -0.0001(2) |
| Se4x1 | 0 | -0.0035(3) |
| Se4y1 | 0.0040(9) | 0 |
| Se4z1 | 0 | 0.0016(2) |
| Se5x1 | 0 | 0.0017(3) |
| Se5y1 | 0.0006(9) | 0 |
| Se5z1 | 0 | 0.0015(2) |
| Se6x1 | 0 | 0.0014(3) |
| Se6y1 | 0.0009(9) | 0 |
| Se6z1 | 0 | 0.0002(2) |
| Se7x1 | 0 | 0.0004(3) |
| Se7y1 | -0.0132(9) | 0 |
| Se7z1 | 0 | 0.0004(3) |
ADP components: (Show/hide table) [ Help ]
| Atom site label | Atom site symbol | U11 | U22 | U33 | U12 | U13 | U23 |
|---|---|---|---|---|---|---|---|
| Ta1 | Ta | 0.014(4) | -0.014(4) | 0.033(4) | 0 | 0.007(2) | 0 |
| Ta2 | Ta | 0.008(4) | -0.011(4) | 0.033(3) | 0 | 0.006(2) | 0 |
| Ni | Ni | 0.010(7) | -0.012(6) | 0.028(6) | 0 | 0.000(4) | 0 |
| Se1 | Se | 0.005(6) | -0.004(5) | 0.030(5) | 0 | 0.005(4) | 0 |
| Se2 | Se | -0.010(5) | 0.005(5) | 0.024(5) | 0 | 0.003(3) | 0 |
| Se3 | Se | 0.022(6) | -0.012(6) | 0.035(6) | 0 | 0.007(4) | 0 |
| Se4 | Se | 0.023(6) | -0.008(5) | 0.033(5) | 0 | 0.007(4) | 0 |
| Se5 | Se | 0.021(7) | -0.009(5) | 0.032(5) | 0 | 0.005(4) | 0 |
| Se6 | Se | 0.015(7) | 0.001(6) | 0.026(5) | 0 | 0.001(4) | 0 |
| Se7 | Se | 0.036(7) | -0.012(5) | 0.042(5) | 0 | 0.013(4) | 0 |