Open with JSmol

KSm(MoO4)2, an incommensurately modulated and partially disordered scheelite-like structure

Authors:

Arakcheeva, Alla; Pattison, Philip; Chapuis, Gervais; Rossell, Marta; Filaretov, Andrey; Morozov, Vladimir; Van Tendeloo, Gustaaf

Journal:

Acta Crystallographica, Section B 64 160-171 (2008)

DOI:

https://doi.org/10.1107/S0108768108001870

B-IncStrDB ID: 8fSpYtV07gu Entry date: 2022-01-24 Last revision: 2022-01-24

Download CIF
Open in JSmol

I

Chemical data

Full Name: potassium samarium molybdenum oxide [ Help ]

Common Name: KSm(MoO4)2 [ Help ]

Formula moiety: (K1+),(Sm3+),(MoO4 2-)2 [ Help ]

Structural Formula Sum: K1 Mo2 O8 Sm1 [ Help ]

Structural Formula: KSm(MoO4)2 [ Help ]

Formula analytical: KSm(MoO4)2 [ Help ]

Formula (IUPAC): KSm(MoO4)2 [ Help ]

Formula weight: 509.3 Da [ Help ]

Crystallographic data and experimental details

Crystal system: monoclinic [ Help ]

Superspace group name: I2/b(αβ0)00 [ Help ]

Symmetry operations of the superspace group: [ Help ]

Operation code Operation in algebraic form
1 x1,x2,x3,x4
2 -x1,-x2+1/2,x3,-x4
3 -x1,-x2,-x3,-x4
4 x1,x2+1/2,-x3,x4
5 x1+1/2,x2+1/2,x3+1/2,x4
6 -x1+1/2,-x2,x3+1/2,-x4
7 -x1+1/2,-x2+1/2,-x3+1/2,-x4
8 x1+1/2,x2,-x3+1/2,x4

a: 5.5279(2) Å [ Help ]

b: 5.2994(2) Å [ Help ]

c: 11.78410(10) Å [ Help ]

α: 90 ° [ Help ]

β: 90 ° [ Help ]

γ: 91.1388(5) ° [ Help ]

Volume: 345.1445 Å3 [ Help ]

Z: 2 [ Help ]

Cell measurement temperature: 273 K [ Help ]

Modulation dimension: 1 [ Help ]

Measured independent wave vectors: [ Help ]

Wave vector id q_x q_y q_z
1 0.56771(5) -0.12682(8) 0.00000

μ: 12.588 mm-1 [ Help ]

Absorption correction type: none [ Help ]

Refinement details

Refinement remarks: Two complementary waves, K and Sm, have been used for the occupation modulation of the (K,Sm) position [ Help ]

R(all): 0.0139 [ Help ]

R(obs): 0.0139 [ Help ]

wR(obs): 0.0160 [ Help ]

wR(all): 0.0160 [ Help ]

Nb. of parameters: 42 [ Help ]

Number of restraints: 1 [ Help ]

Weighting scheme: sigma [ Help ]

Δ/σ(max): 0.0018 [ Help ]

Δ/σ(mean): 0.0002 [ Help ]

Extinction method: none [ Help ]

Structural Information

Average Structure: [ Help ]

Atom symbol Atom site label x y z Uiso/equiv ADP type Coords from (d)iffraction or (c)alculated Coords restraints or constraints Occupancy Disordered cluster Disordered group
K K 0.5 0.25 0.866136 0.0251 Uiso d . 0.5 . .
Sm Sm 0.5 0.25 0.8780(5) 0.0001(3) Uiso d . 0.5 . .
Mo Mo 0.5 0.25 0.37801(8) 0.0126(2) Uiso d . 1 . .
O O1 0.3543(3) 0.0109(4) 0.29180(17) 0.0093(8) Uiso d . 1 . .
O O2 0.7632(5) 0.3985(4) 0.04196(18) 0.0225(9) Uiso d . 1 . .

Fourier Wave Vectors (explicit: q_x,q_y,q_z or coefficients: q_1,q_2,...): [ Help ]

Wave vector code q_x q_y q_z
1 0.56771 -0.12682 0.00000
2 1.13542 -0.25364 0.00000
3 1.70313 -0.38046 0.00000

Definition of the displacive (translational) Fourier series: [ Help ]

Modulation code Atom site label Displacement axis Wave vector code
Kx1 K x 1
Ky1 K y 1
Kz1 K z 1
Smx1 Sm x 1
Smy1 Sm y 1
Smz1 Sm z 1
Smx2 Sm x 2
Smy2 Sm y 2
Smz2 Sm z 2
Mox1 Mo x 1
Moy1 Mo y 1
Moz1 Mo 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: [ Help ]

Modulation code Cosine coefficient Sine coefficient
Kx1 0 -0.0531(9)
Ky1 0 0.0025(14)
Kz1 0.019 0
Smx1 0 0.0130(8)
Smy1 0 0.0358(7)
Smz1 0.00344(13) 0
Smx2 0 0.0026(10)
Smy2 0 0.0261(8)
Smz2 0.0055(3) 0
Mox1 0 0.0332(2)
Moy1 0 -0.00630(19)
Moz1 0.01375(13) 0
O1x1 0.0016(8) 0.0273(8)
O1y1 0.0251(9) 0.0070(9)
O1z1 0.0070(3) -0.0120(4)
O2x1 0.0346(7) 0.0138(7)
O2y1 0.0135(10) -0.0258(10)
O2z1 -0.0057(4) 0.0015(4)

Definition of the occupation Fourier series: [ Help ]

Modulation code Atom site label Wave vector code
Ko1 K 1
Ko2 K 2
Ko3 K 3
Moo1 Sm 1
Moo2 Sm 2
Moo3 Sm 3

Occupation Fourier coefficients: [ Help ]

Modulation code Cosine coefficient Sine coefficient
Ko1 0.5780(11) 0
Ko2 0.003(5) 0
Ko3 -0.1697(18) 0
Moo1 -0.5780(11) 0
Moo2 -0.003(5) 0
Moo3 0.1697(18) 0