perovskite atlas Structures, modes and phase transitions · Josu M. Igartua · UPV/EHU

CaPr2CuTi2O9 · Pbnm · 300 K

CaPr2CuTi2O9 · Pbnm · 300 K

status published · visibility public · id str:capr2cuti2o9.pbnm.300k.iturbe2012

Material
CaPr2CuTi2O9
Space group
Pbnm · No. 62
Setting
Pbnm (non-standard setting of Pnma, No. 62)
Phase
room temperature
Temperature
300 K

fer document ↗ standardised version of this record

Cell

a (Å) b (Å) c (Å) α (°) β (°) γ (°) V (ų)
5.4821(1) 5.5942(1) 7.6869(1) 90 90 90

Atoms

label element Wyckoff x y z occ. Biso (Ų)
Ca/Pr Ca 4c -0.0069(5) -0.0452(3) 0.75 0.35/0.65 0.34(5)
Cu/Ti Cu 4b 0.5 0 0 0.35/0.65 0.5 (fixed)
O1 O 4c 0.423(3) 0.019(2) 0.75 1 0.7(2)
O2 O 8d 0.203(2) 0.789(2) 0.459(1) 1 0.7(2)

Structure for calculations

CIF: absent. Bilbao Crystallographic Server input (AMPLIMODES, SYMMODES, PSEUDO), uncertainties stripped:

# Perovskite Atlas · str:capr2cuti2o9.pbnm.300k.iturbe2012
# Space group Pbnm (No. 62) · setting: Pbnm (non-standard setting of Pnma, No. 62)
# BCS structure format: space-group number / cell / number of atoms / element index Wyckoff x y z
62
5.4821 5.5942 7.6869 90 90 90
4
Ca 1 4c -0.0069 -0.0452 0.75   # Ca/Pr, occupancy 0.35/0.65
Cu 1 4b 0.5 0 0   # Cu/Ti, occupancy 0.35/0.65
O 1 4c 0.423 0.019 0.75   # O1
O 2 8d 0.203 0.789 0.459   # O2
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Refinement

software method variant Rp Rwp Rexp RBragg χ² parameters
FullProf symmetry-mode all-modes 1.74

Symmetry-mode decomposition

fer document ↗ standardised version of this record

Parent
Pm3m
Software
AMPLIMODES
Convention
amplimodes-cell
Variant
all-modes
irrep k direction dim isotropy subgroup amplitude (Å) role physical meaning
R4+ (1/2,1/2,1/2) 1 Imma 1.20(1) primary antiphase octahedral tilt
R5+ (1/2,1/2,1/2) 2 Imma 0.03(1) octahedral deformation
X5+ (0,1/2,0) 2 Cmcm 0.24(1) A-site antipolar displacement
M2+ (1/2,1/2,0) 1 P4/mbm 0.01(1) octahedral deformation
M3+ (1/2,1/2,0) 1 P4/mbm 1.03(1) primary in-phase octahedral tilt

Geometry (as reported)

fer document ↗ standardised version of this record

Bond angles

angle value (°)
a/Ln-O1(×1)(Å) 3.19(1)
a/Ln_-O2(×2)(Å) 2.68(1)
a/Ln-O2(×2)(Å) 3.36(1)
a/Ln-O>8short^a(Å) 2.54(2)
u/Ti-O1_ax(×2)(Å) 1.97(1)
u/Ti-O2_eq(×2)(Å) 1.99(1)
u/Ti-O2^′_eq(×2)(Å) 2.04(1)
u/Ti-O>(Å) 2.00(1)
O1_ax-Cu/Ti-O2_eq(^°) 89.4(3)
O1_ax-Cu/Ti-O2′_eq(°) 89.5(2)
O2_eq-Cu/Ti-O2′_eq(°) 90.0(2)
Cu/Ti-O1_ax-Cu/Ti(^°) 154.5(5)
Cu/Ti-O2_eq-Cu/Ti(^°) 153.3(3)

Rietveld refinement of NPD data by symmetry-mode parametrisation (AMPLIMODES for FullProf). Original files expected from data rescue.

Evidence