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Single-crystal X-ray diffraction data [synchrotron radiation; λ = 1.2682 (4) Å] are used to solve and refine the crystal structure of heptacalcium hexatantalum heptazirconium hexatriacontaoxide, Ca7Zr7Ta6O36. The structure adopts space group Fddd with cell dimensions a = 36.394 (1), b = 7.3674 (5), c = 31.006 (2) Å. The structure was solved by direct methods. Refinement using 1299 unique reflections leads to final values of R = 0.031 and wR = 0.034. The refined metal-atom ordering scheme is far from fully ordered and reminiscent of the A/B metal-atom ordering characteristic of the pyrochlore structure type. Bond-valence sums are calculated to confirm the plausibility of the crystal chemistry of Ca7Zr7Ta6O36.

Supporting information

cif

Crystallographic Information File (CIF)
Contains datablock final

sft

Structure factor file (SHELXL table format)
Supplementary material

Computing details top

Data collection: Tsukuba BL-14A software; cell refinement: Tsukuba BL-14A software; data reduction: xtal_DIFDAT_ADDREF_SORTRF; program(s) used to solve structure: xtal_GENTAN and SHELX97; program(s) used to refine structure: xtal_CRYLSQ and RAELS95; molecular graphics: CrystalMaker; software used to prepare material for publication: xtal_BONDLA_CIFIO.

calcium zirconium tantalum oxide top
Crystal data top
Ca7O36Ta6Zr7F(000) = 13752
Mr = 2580.78Dx = 6.186 Mg m3
Orthorhombic, FdddXray radiation, λ = 1.2682 (4) Å
Hall symbol: -F 2uv 2vwCell parameters from 24 reflections
a = 36.394 (1) Åθ = 16.5–24°
b = 7.3674 (5) ŵ = 42.71 mm1
c = 31.006 (2) ÅT = 293 K
V = 8313.2 (12) Å3Square_prism, white
Z = 120.02 × 0.01 × 0.01 mm
Data collection top
Tsukuba_BL14A
diffractometer
Rint = 0.039
Radiation source: synchrotronθmax = 50.1°, θmin = 3.1°
Si(111)_double_crystal monochromatorh = 4443
θ/2θ scansk = 88
0.123370+05 measured reflectionsl = 3437
1928 independent reflections9 standard reflections every 200/100 reflections
1299 reflections with I > 2σ(I) intensity decay: none
Refinement top
Refinement on F0 restraints
Least-squares matrix: full0 constraints
R[F2 > 2σ(F2)] = 0.031
wR(F2) = 0.038(Δ/σ)max = 0.021
S = 1.38Δρmax = 1.41 e Å3
1299 reflectionsΔρmin = 2.08 e Å3
195 parameters
Special details top

Refinement. Sfls: F calc weight full matrix

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/UeqOcc. (<1)
Ta10.01975 (2)0.375000.875000.0045 (4)0.62
Zr10.01975 (2)0.375000.875000.0045 (4)0.38
Ta20.02395 (2)0.375000.375000.0039 (4)0.85
Zr20.02395 (2)0.375000.375000.0039 (4)0.15
Ta30.074378 (18)0.12299 (8)0.458627 (14)0.0039 (3)0.80
Zr30.074378 (18)0.12299 (8)0.458627 (14)0.0039 (3)0.20
Ta40.12253 (2)0.36635 (8)0.202284 (18)0.0065 (3)0.45
Zr40.12253 (2)0.36635 (8)0.202284 (18)0.0065 (3)0.55
Ta50.06757 (3)0.125000.125000.0113 (5)0.23
Zr50.06757 (3)0.125000.125000.0113 (5)0.77
Ta60.03224 (2)0.37420 (16)0.03484 (2)0.0069 (4)0.13
Zr60.03224 (2)0.37420 (16)0.03484 (2)0.0069 (4)0.87
Ca70.07788 (5)0.1453 (3)0.29208 (6)0.0228 (10)0.81
Zr70.07788 (5)0.1453 (3)0.29208 (6)0.0228 (10)0.19
Ca80.02322 (5)0.8705 (4)0.03899 (5)0.0086 (8)0.92
Zr80.02322 (5)0.8705 (4)0.03899 (5)0.0086 (8)0.08
Ca90.11849 (7)0.375000.875000.0230 (12)0.78
Zr90.11849 (7)0.375000.875000.0230 (12)0.22
Ca100.07446 (7)0.625000.125000.0047 (11)
Zr100.07446 (7)0.625000.125000.0047 (11)0.0
O10.125000.625000.0725 (2)0.006 (4)
O20.01909 (16)0.5821 (8)0.0803 (2)0.008 (3)
O30.02361 (15)0.1223 (10)0.1005 (2)0.013 (3)
O40.03071 (17)0.1449 (11)0.0002 (2)0.011 (3)
O50.08503 (17)0.4303 (8)0.0020 (2)0.009 (3)
O60.0761 (2)0.9129 (9)0.0834 (2)0.017 (4)
O70.08621 (18)0.8215 (8)0.0001 (2)0.011 (3)
O80.02478 (14)0.6069 (11)0.0139 (2)0.009 (3)
O90.06362 (18)0.4293 (8)0.0840 (2)0.012 (3)
O100.125000.125000.0155 (3)0.018 (5)
O110.01802 (18)0.1812 (9)0.0855 (2)0.014 (4)
O120.125000.625000.0665 (3)0.016 (4)
O130.0794 (2)0.3315 (9)0.0800 (2)0.019 (4)
O140.0627 (2)0.8242 (9)0.0820 (2)0.018 (4)
O150.125000.125000.0847 (3)0.030 (6)
O160.125000.125000.0989 (5)0.070 (10)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Ta10.0042 (4)0.0057 (4)0.0037 (4)0.000000.000000.0001 (5)
Zr10.0042 (4)0.0057 (4)0.0037 (4)0.000000.000000.0001 (5)
Ta20.0042 (4)0.0039 (4)0.0038 (3)0.000000.000000.0004 (5)
Zr20.0042 (4)0.0039 (4)0.0038 (3)0.000000.000000.0004 (5)
Ta30.0038 (3)0.0049 (3)0.0030 (3)0.0009 (3)0.00001 (17)0.0003 (4)
Zr30.0038 (3)0.0049 (3)0.0030 (3)0.0009 (3)0.00001 (17)0.0003 (4)
Ta40.0031 (3)0.0084 (3)0.0082 (3)0.0004 (4)0.0005 (2)0.0044 (2)
Zr40.0031 (3)0.0084 (3)0.0082 (3)0.0004 (4)0.0005 (2)0.0044 (2)
Ta50.0069 (5)0.0031 (5)0.0237 (5)0.000000.000000.0005 (6)
Zr50.0069 (5)0.0031 (5)0.0237 (5)0.000000.000000.0005 (6)
Ta60.0074 (4)0.0062 (4)0.0072 (3)0.0013 (4)0.0013 (3)0.0017 (4)
Zr60.0074 (4)0.0062 (4)0.0072 (3)0.0013 (4)0.0013 (3)0.0017 (4)
Ca70.0136 (10)0.0324 (11)0.0222 (9)0.0024 (9)0.0145 (6)0.0103 (11)
Zr70.0136 (10)0.0324 (11)0.0222 (9)0.0024 (9)0.0145 (6)0.0103 (11)
Ca80.0080 (9)0.0084 (8)0.0094 (8)0.0002 (7)0.0022 (6)0.0031 (10)
Zr80.0080 (9)0.0084 (8)0.0094 (8)0.0002 (7)0.0022 (6)0.0031 (10)
Ca90.0388 (16)0.0103 (10)0.0200 (12)0.000000.000000.0099 (9)
Zr90.0388 (16)0.0103 (10)0.0200 (12)0.000000.000000.0099 (9)
Ca100.0031 (10)0.0079 (12)0.0031 (10)0.000000.000000.0011 (14)
Zr100.0031 (10)0.0079 (12)0.0031 (10)0.000000.000000.0011 (14)
O10.006 (4)0.003 (4)0.011 (4)0.004 (4)0.000000.00000
O20.009 (3)0.005 (4)0.009 (3)0.001 (2)0.001 (2)0.003 (2)
O30.016 (3)0.009 (3)0.014 (3)0.003 (3)0.001 (2)0.007 (3)
O40.014 (3)0.008 (3)0.012 (3)0.002 (3)0.005 (3)0.001 (3)
O50.008 (3)0.012 (4)0.008 (3)0.000 (2)0.000 (3)0.007 (2)
O60.039 (4)0.009 (4)0.004 (3)0.011 (3)0.004 (3)0.002 (3)
O70.017 (3)0.009 (4)0.006 (3)0.004 (3)0.002 (3)0.004 (2)
O80.003 (3)0.013 (4)0.010 (3)0.001 (3)0.001 (2)0.004 (3)
O90.010 (3)0.013 (4)0.011 (3)0.006 (3)0.001 (3)0.002 (3)
O100.017 (5)0.010 (4)0.028 (5)0.010 (5)0.000000.00000
O110.012 (3)0.019 (4)0.011 (3)0.004 (3)0.005 (3)0.002 (3)
O120.009 (4)0.029 (5)0.011 (4)0.000 (5)0.000000.00000
O130.031 (4)0.019 (4)0.007 (3)0.016 (3)0.009 (3)0.006 (3)
O140.023 (4)0.019 (4)0.012 (3)0.006 (3)0.009 (3)0.001 (3)
O150.033 (6)0.034 (6)0.023 (5)0.009 (6)0.000000.00000
O160.073 (10)0.062 (10)0.074 (10)0.002 (10)0.000000.00000
Bond lengths (Å) top
Ta1—O3i2.016 (7)Zr6—O112.181 (7)
Ta1—O9i2.080 (6)Zr6—O132.238 (7)
Ta1—O2ii2.004 (6)Zr6—O8xiii2.179 (5)
Ta1—O2iii2.004 (6)Ca7—O3v2.683 (6)
Ta1—O3iv2.016 (7)Ca7—O4v2.173 (7)
Ta1—O9iv2.080 (6)Ca7—O5v2.773 (6)
Zr1—O3i2.016 (7)Ca7—O9v2.770 (7)
Zr1—O9i2.080 (6)Ca7—O10v2.481 (7)
Zr1—O2ii2.004 (6)Ca7—O15v2.170 (7)
Zr1—O2iii2.004 (6)Ca7—O7vi2.477 (6)
Zr1—O3iv2.016 (7)Ca7—O14vi2.472 (7)
Zr1—O9iv2.080 (6)Zr7—O3v2.683 (6)
Ta2—O3v1.974 (7)Zr7—O4v2.173 (7)
Ta2—O14vi1.976 (7)Zr7—O5v2.773 (6)
Ta2—O14vii1.976 (7)Zr7—O9v2.770 (7)
Ta2—O3viii1.974 (7)Zr7—O10v2.481 (7)
Ta2—O11ix2.001 (7)Zr7—O15v2.170 (7)
Ta2—O11x2.001 (7)Zr7—O7vi2.477 (6)
Zr2—O3v1.974 (7)Zr7—O14vi2.472 (7)
Zr2—O14vi1.976 (7)Ca8—O22.486 (6)
Zr2—O14vii1.976 (7)Ca8—O62.387 (7)
Zr2—O3viii1.974 (7)Ca8—O72.619 (7)
Zr2—O11ix2.001 (7)Ca8—O82.543 (8)
Zr2—O11x2.001 (7)Ca8—O4xiv2.374 (8)
Ta3—O5vii1.994 (6)Ca8—O11xiv2.711 (7)
Ta3—O7vii1.990 (6)Ca8—O3xiii2.558 (6)
Ta3—O8vii1.999 (5)Ca8—O4xiii2.304 (7)
Ta3—O9vii1.984 (6)Zr8—O22.486 (6)
Ta3—O12vii2.000 (3)Zr8—O62.387 (7)
Ta3—O14vii1.992 (7)Zr8—O72.619 (7)
Zr3—O5vii1.994 (6)Zr8—O82.543 (8)
Zr3—O7vii1.990 (6)Zr8—O4xiv2.374 (8)
Zr3—O8vii1.999 (5)Zr8—O11xiv2.711 (7)
Zr3—O9vii1.984 (6)Zr8—O3xiii2.558 (6)
Zr3—O12vii2.000 (3)Zr8—O4xiii2.304 (7)
Zr3—O14vii1.992 (7)Ca9—O9i2.401 (7)
Ta4—O10v2.041 (5)Ca9—O12i2.596 (6)
Ta4—O16v2.384 (11)Ca9—O15i2.238 (6)
Ta4—O1vi2.057 (3)Ca9—O14xv2.862 (7)
Ta4—O6vi2.031 (7)Ca9—O9iv2.401 (7)
Ta4—O7vi2.039 (6)Ca9—O12iv2.596 (6)
Ta4—O5xi2.148 (6)Ca9—O15iv2.238 (6)
Ta4—O13xi2.032 (7)Ca9—O14xvi2.862 (7)
Zr4—O10v2.041 (5)Zr9—O9i2.401 (7)
Zr4—O16v2.384 (11)Zr9—O12i2.596 (6)
Zr4—O1vi2.057 (3)Zr9—O15i2.238 (6)
Zr4—O6vi2.031 (7)Zr9—O14xv2.862 (7)
Zr4—O7vi2.039 (6)Zr9—O9iv2.401 (7)
Zr4—O5xi2.148 (6)Zr9—O12iv2.596 (6)
Zr4—O13xi2.032 (7)Zr9—O15iv2.238 (6)
Ta5—O112.219 (7)Zr9—O14xvi2.862 (7)
Ta5—O132.109 (7)Ca10—O12.456 (5)
Ta5—O162.242 (6)Ca10—O22.466 (6)
Ta5—O6xii2.050 (7)Ca10—O62.483 (7)
Ta5—O11v2.219 (7)Ca10—O132.579 (7)
Ta5—O13v2.109 (7)Ca10—O1vi2.456 (5)
Ta5—O16v2.242 (6)Ca10—O2vi2.466 (6)
Ta5—O6vi2.050 (7)Ca10—O6vi2.483 (7)
Zr5—O112.219 (7)Ca10—O13vi2.579 (7)
Zr5—O132.109 (7)Zr10—O12.456 (5)
Zr5—O162.242 (6)Zr10—O22.466 (6)
Zr5—O6xii2.050 (7)Zr10—O62.483 (7)
Zr5—O11v2.219 (7)Zr10—O132.579 (7)
Zr5—O13v2.109 (7)Zr10—O1vi2.456 (5)
Zr5—O16v2.242 (6)Zr10—O2vi2.466 (6)
Zr5—O6vi2.050 (7)Zr10—O6vi2.483 (7)
Ta6—O22.136 (6)Zr10—O13vi2.579 (7)
Ta6—O42.009 (8)O5—O82.597 (9)
Ta6—O52.213 (6)O5—O132.533 (9)
Ta6—O82.302 (7)O6—O16xiv2.416 (8)
Ta6—O112.181 (7)O8—O8xiii2.545 (9)
Ta6—O132.238 (7)O10—O162.584 (18)
Ta6—O8xiii2.179 (5)O11—O132.500 (10)
Zr6—O22.136 (6)O11—O11v2.585 (9)
Zr6—O42.009 (8)O13—O162.326 (8)
Zr6—O52.213 (6)O16—O16v1.62 (2)
Zr6—O82.302 (7)
Symmetry codes: (i) x, y, z+1; (ii) x, y+1, z+1; (iii) x, y1/4, z+3/4; (iv) x, y+3/4, z+3/4; (v) x, y+1/4, z+1/4; (vi) x, y+5/4, z+1/4; (vii) x, y1/2, z+1/2; (viii) x, y+1/2, z+1/2; (ix) x, y+1/2, z+1/2; (x) x, y+1/4, z+1/4; (xi) x+1/4, y, z+1/4; (xii) x, y1, z; (xiii) x, y+1, z; (xiv) x, y+1, z; (xv) x+1/4, y+5/4, z+1; (xvi) x+1/4, y1/2, z+3/4.
 
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