Incommensurately modulated ordering of tetrahedral chains in Ca2Fe2O5 at elevated temperatures
Authors:Kruger, Hannes; Kahlenberg, Volker
Journal:Acta Crystallographica, Section B 61 656-662 (2005)
DOI:https://doi.org/10.1107/S0108768105026480
B-IncStrDB ID: 3PT6kctL7aU Entry date: 2022-01-28 Last revision: 2022-01-28
I
Chemical data
Structural Formula Sum: Ca2 Fe2 O5 [ Help ]
Formula weight: 271.8 Da [ Help ]
Crystallographic data and experimental details
Crystal system: orthorhombic [ Help ]
Superspace group name: Imma(00γ)s00 [ 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 | x1,1/2-x2,x3,x4 |
| 4 | -x1,1/2-x2,x3,1/2+x4 |
| 5 | -x1,-x2,-x3,-x4 |
| 6 | x1,-x2,-x3,1/2-x4 |
| 7 | -x1,1/2+x2,-x3,-x4 |
| 8 | x1,1/2+x2,-x3,1/2-x4 |
| 9 | 1/2+x1,1/2+x2,1/2+x3,x4 |
| 10 | 1/2-x1,1/2+x2,1/2+x3,1/2+x4 |
| 11 | 1/2+x1,-x2,1/2+x3,x4 |
| 12 | 1/2-x1,-x2,1/2+x3,1/2+x4 |
| 13 | 1/2-x1,1/2-x2,1/2-x3,-x4 |
| 14 | 1/2+x1,1/2-x2,1/2-x3,1/2-x4 |
| 15 | 1/2-x1,x2,1/2-x3,-x4 |
| 16 | 1/2+x1,x2,1/2-x3,1/2-x4 |
a: 5.4931(12) Å [ Help ]
b: 15.038(3) Å [ Help ]
c: 5.6511(11) Å [ Help ]
α: 90 ° [ Help ]
β: 90 ° [ Help ]
γ: 90 ° [ Help ]
Volume: 466.79(17) Å3 [ Help ]
Modulation dimension: 1 [ Help ]
Measured independent wave vectors: (Show/hide table) [ Help ]
| Wave vector id | q_x | q_y | q_z |
|---|---|---|---|
| 1 | 0.00000 | 0.00000 | 0.588(2) |
Z: 4 [ Help ]
Cell determination reflection Nb.: 2473 [ Help ]
θ(min) for cell determination: 2.71 ° [ Help ]
θ(max) for cell determination: 29.54 ° [ Help ]
Cell measurement temperature: 1100 K [ Help ]
μ: 8.331 mm-1 [ Help ]
Absorption correction type: integration [ Help ]
Absorption correction remarks: STOE X-RED [ Help ]
Minimum transmission factor: 0.3086 [ Help ]
Maximum transmission factor: 0.6093 [ Help ]
Refinement details
Total nb. of reflections: 934 [ Help ]
Nb. of observed reflections: 759 [ Help ]
Intense reflections threshold: I>3σ(I) [ Help ]
Refinement based on: F [ Help ]
R(obs): 0.0530 [ Help ]
wR(obs): 0.0535 [ Help ]
R(all): 0.0667 [ Help ]
wR(all): 0.0550 [ Help ]
S(all): 2.91 [ Help ]
S(obs): 3.15 [ Help ]
Nb. of reflections: 934 [ Help ]
Nb. of parameters: 43 [ Help ]
Weighting scheme: sigma [ Help ]
Weighting scheme remarks: w=1/(σ2(F)+0.0001F2) [ Help ]
Δ/σ(max): 0.0010 [ Help ]
Δ/σ(mean): 0.0001 [ Help ]
Δρ(max): 1.29 e_Å-3 [ Help ]
Δρ(min): -1.96 e_Å-3 [ Help ]
Extinction method: none [ Help ]
Structural Information
Average Structure: (Show/hide table) [ Help ]
| Atom site label | Atom symbol | x | y | z | ADP type | Uiso/equiv | Symmetry multiplicity | Occupancy | Coords from (d)iffraction or (c)alculated | Coords restraints or constraints | Disordered cluster | Disordered group |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Fe1 | Fe | 0 | 0 | 0.5 | Uani | 0.0218(2) | 4 | 1 | d | . | . | . |
| Fe2 | Fe | 0.94636(15) | 0.25 | 0.56859(18) | Uani | 0.0203(2) | 8 | 1 | d | . | . | . |
| Ca1 | Ca | 0 | 0.10808(7) | 0.02377(19) | Uani | 0.0304(3) | 8 | 1 | d | . | . | . |
| O1 | O | 0.75 | 0.0131(2) | 0.75 | Uani | 0.0259(9) | 8 | 1 | d | . | . | . |
| O2 | O | 0 | 0.1413(2) | 0.4317(7) | Uani | 0.0370(11) | 8 | 1 | d | . | . | . |
| O3 | O | 0.4021(7) | 0.25 | 0.6255(9) | Uani | 0.0265(14) | 8 | 1 | d | . | . | . |
ADP components: (Show/hide table) [ Help ]
| Atom site label | Atom site symbol | U11 | U22 | U33 | U12 | U13 | U23 |
|---|---|---|---|---|---|---|---|
| Fe1 | Fe | 0.0133(3) | 0.0378(5) | 0.0142(4) | 0 | 0 | -0.0010(4) |
| Fe2 | Fe | 0.0234(4) | 0.0163(4) | 0.0213(5) | 0 | -0.0001(3) | 0 |
| Ca1 | Ca | 0.0395(5) | 0.0233(4) | 0.0284(5) | 0 | 0 | 0.0008(4) |
| O1 | O | 0.0178(12) | 0.0364(17) | 0.0236(16) | 0 | 0.0094(12) | 0 |
| O2 | O | 0.052(2) | 0.0231(16) | 0.036(2) | 0 | 0 | -0.0070(16) |
| O3 | O | 0.0187(19) | 0.031(3) | 0.030(3) | 0 | -0.0051(17) | 0 |
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 | 0.00000 | 0.00000 | 0.58800 |
Occupation crenel coefficients: (Show/hide table) [ Help ]
| Atom site label | Center (x0) | Width |
|---|---|---|
| Fe2 | 0.6451 | 0.5 |
| O3 | 0.178(3) | 0.5 |
Definition of the displacive (translational) Fourier series: (Show/hide table) [ Help ]
| Modulation code | Atom site label | Displacement axis | Wave vector code |
|---|---|---|---|
| Fe1x1 | Fe1 | x | 1 |
| Fe1y1 | Fe1 | y | 1 |
| Fe1z1 | Fe1 | z | 1 |
| Ca1x1 | Ca1 | x | 1 |
| Ca1y1 | Ca1 | y | 1 |
| Ca1z1 | Ca1 | z | 1 |
| O1x1 | O1 | x | 1 |
| O1y1 | O1 | y | 1 |
| O1z1 | O1 | z | 1 |
| O2x1 | O2 | x | 1 |
| O2y1 | O2 | y | 1 |
| O2z1 | O2 | z | 1 |
Displacive (translational) Fourier coefficients: (Show/hide table) [ Help ]
| Modulation code | Cosine coefficient | Sine coefficient |
|---|---|---|
| Fe1x1 | 0 | 0.00333(17) |
| Fe1y1 | 0 | 0 |
| Fe1z1 | 0 | 0 |
| Ca1x1 | -0.0115(2) | 0.0088(2) |
| Ca1y1 | 0 | 0 |
| Ca1z1 | 0 | 0 |
| O1x1 | 0 | 0.0039(6) |
| O1y1 | -0.0015(3) | 0 |
| O1z1 | 0 | 0.0023(9) |
| O2x1 | -0.0191(9) | -0.0039(9) |
| O2y1 | 0 | 0 |
| O2z1 | 0 | 0 |