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

Sr2Co0.5Mg0.5TeO6 · I2/m · 300 K

Sr2Co0.5Mg0.5TeO6 · I2/m · 300 K

status published · visibility public · id str:sr2co0.5mg0.5teo6.i2m.300k.orayech2015

Material
Sr2Co0.5Mg0.5TeO6
Space group
I2/m · No. 12
Setting
I 1 2/m 1 (non-standard setting of C2/m, No. 12)
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)
5.6230(1) 5.5968(1) 7.9060(1) 90 89.985(1) 90 248.83(1)

Atoms

label element Wyckoff x y z occ. Biso (Ų)
Sr Sr 4i 0.006(5) 0.5 -0.7553(12) 1 0.97(3)
O1 O 8j 0.235(6) 0.271(6) -0.017(7) 1 1.06
O2 O 4i 0.075(1) 0 -0.748(6) 1 1.06
Te Te 2a 0 0 0 1 1.56(1)
Co/Mg Co 2d 0 0 0.5 0.5/0.5 (Co/Mg) 1.56(1)

Structure for calculations

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

# Perovskite Atlas · str:sr2co0.5mg0.5teo6.i2m.300k.orayech2015
# Space group I2/m (No. 12) · setting: I 1 2/m 1 (non-standard setting of C2/m, No. 12)
# BCS structure format: space-group number / cell / number of atoms / element index Wyckoff x y z
12
5.6230 5.5968 7.9060 90 89.985 90
5
Sr 1 4i 0.006 0.5 -0.7553   # Sr
O 1 8j 0.235 0.271 -0.017   # O1
O 2 4i 0.075 0 -0.748   # O2
Te 1 2a 0 0 0   # Te
Co 1 2d 0 0 0.5   # Co/Mg, occupancy 0.5/0.5 (Co/Mg)
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Refinement

software method variant Rp Rwp Rexp RBragg χ² parameters
FullProf symmetry-mode all-modes 11.3

Symmetry-mode decomposition

fer document ↗ standardised version of this record

Parent
Fm3m
Transformation
a+b, -a+b, c (Table 9.1; origin shift as given there)
Software
AMPLIMODES
Convention
amplimodes-cell
Variant
all-modes
irrep k direction dim isotropy subgroup amplitude (Å) role physical meaning
GM1+ (0,0,0) 1 Fm3m 0.1102(3)
GM3+ (0,0,0) 1 I4/mmm 0.0075(6)
GM4+ (0,0,0) 1 C2/m 0.6174(6) primary octahedral rotation about the monoclinic b axis (pseudo-cubic [110])
GM5+ (0,0,0) 4 C2/m 0.0866(5)

Geometry (as reported)

fer document ↗ standardised version of this record

Octahedra: bond lengths, mean and predicted (bond-valence) distances, volumes

octahedron bond length (Å) predicted (Å) V (ų)
Co/MgO6 mean 2.023(6) 2.0985
TeO6 mean 1.978(6) 1.9170

Bond lengths

bond length (Å)
Co/Mg-O1(×4) 2.020(1)
Co/Mg-O2(×2) 2.029(2)
Te-O1(×4) 1.975(1)
Te-O2(×2) 1.985(2)

Bond angles

angle value (°)
O1-Co/Mg-O2 89.9(2)
O1-Co/Mg-O3(×2) 90.0(7)
O1-Te-O2 89.9(4)
O1-Te-O3(×2) 90.1(4)
Co/Mg-O1-Te 165.7(5)
Co/Mg-O2-Te(×2) 159.6(8)

Column (a) of Table 9.3 (all mode amplitudes refined). Te and Co/Mg have no refined coordinates (special positions); their Wyckoff labels are assigned from the space-group setting and marked fixed. Original FullProf files expected from data rescue.

Evidence