Synchrotron study of pyrochlore-related NaCdZn₂F₇

The crystal structure of pyrochlore-related NaCdZn₂F₇ (sodium cadmium dizinc hepta­fluoride) has been determined via synchrotron diffraction. Zn is octa­hedrally coordinated by fluorine. Na and Cd are both coordinated by eight anions. Despite the different chemical characteristics and valences, no indication of ordering of Na and Cd was observed.

Key indicators

• Single-crystal synchrotron study
• T = 293 K
• Mean [sigma](Wave) = 0.000 Å
• R factor = 0.032
• wR factor = 0.039
• Data-to-parameter ratio = 36.7

checkCIF/PLATON results

No syntax errors found



Alert level C
CELLV02_ALERT_1_C  The supplied cell volume s.u. differs from that
            calculated from the cell parameter s.u.'s by > 2
            Calculated cell volume su =       5.56
            Cell volume su given      =       3.00
DIFMX01_ALERT_2_C  The maximum difference density is > 0.1*ZMAX*0.75
            _refine_diff_density_max given =      3.970
            Test value =      3.600
DIFMX02_ALERT_1_C  The minimum difference density is > 0.1*ZMAX*0.75
            The relevant atom site should be identified.
GOODF01_ALERT_2_C  The least squares goodness of fit parameter lies
            outside the range 0.80 <> 2.00
            Goodness of fit given =      2.300

Alert level G
  ABSMU_01  Radiation type not identified. Calculation of
            _exptl_absorpt_correction_mu not performed.
ABSTM02_ALERT_3_G  The ratio of expected to reported Tmax/Tmin(RR') is < 0.90
            Tmin and Tmax reported:      0.265     0.497
            Tmin' and Tmax expected:      0.586     0.903
            RR' =      0.822
            Please check that your absorption correction is appropriate.
REFLT03_ALERT_4_G Please check that the estimate of the number of Friedel pairs is
            correct. If it is not, please give the correct count in the
            _publ_section_exptl_refinement section of the submitted CIF.
           From the CIF: _diffrn_reflns_theta_max           31.80
           From the CIF: _reflns_number_total                404
           Count of symmetry unique reflns            0
           Completeness (_total/calc)     +++++++++++++%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured       404
           Fraction of Friedel pairs measured++++++++++
           Are heavy atom types Z>Si present        yes

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   4 ALERT level C = Check and explain
   2 ALERT level G = General alerts; check

   2 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   2 ALERT type 2 Indicator that the structure model may be wrong or deficient
   1 ALERT type 3 Indicator that the structure quality may be low
   1 ALERT type 4 Improvement, methodology, query or suggestion

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Computing details

Data collection: DIF4 (Eichhorn & Lippmann, 2001); cell refinement: LeBail fit of synchrotron powder data (JANA2000; Petřiček & Dušek, 2000); data reduction: REDUCE (Eichhorn, 1995) and AVSORT (Eichhorn, 1992); program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: JANA2000; molecular graphics: ATOMS (Dowty, 1999); software used to prepare material for publication: JANA2000'.

sodium cadmium dizinc heptafluoride

Crystal data

NaCdZn2F7	Dx = 4.786 Mg m^−3
Mr = 399.13	Synchrotron radiation, λ = 0.45 Å
Cubic, Fd3m	Cell parameters from 67 reflections
Hall symbol: -F 4vw 2vw 3	θ = 3–35.0°
a = 10.34657 (3) Å	µ = 8.90 mm^−1
V = 1107.62 (1) Å^3	T = 293 K
Z = 8	Irregular, colourless
F(000) = 1456	0.06 × 0.04 × 0.01 mm
LeBail fit of powder data

Data collection

Beamline D3 four-circle diffractometer	324 reflections with I > 3σ(I)
Radiation source: Hasylab, Hamburg, Germany	Rint = 0.054
Double crystal Si (111) monochromator	θmax = 31.8°, θmin = 1.5°
ω scans	h = −7→24
Absorption correction: numerical (JANA2000; Petřiček & Dušek, 2000)	k = −24→24
Tmin = 0.265, Tmax = 0.497	l = −24→23
8160 measured reflections	2 standard reflections every 45 min min
404 independent reflections	intensity decay: none

Refinement

Refinement on F	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F > 3σ(F)] = 0.032	w = 1/[σ^2(Fo) + (0.01Fo)^2]
wR(F) = 0.039	(Δ/σ)max = −0.014
S = 2.30	Δρmax = 3.97 e Å^−3
404 reflections	Δρmin = −1.18 e Å^−3
11 parameters	Extinction correction: Gaussian Type I (Becker & Coppens, 1974)
3 restraints	Extinction coefficient: 0.21 (2)

Special details

Refinement. We therefore give the results based on these data. For the refinement, an instability factor of 0.01 was used. This instrument-dependent value was extrapolated on the basis of the fluctuations of the integrated intensities of the two standard reflections and their corresponding standard deviations.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq	Occ. (<1)
Na	0	0	0	0.01952 (5)	0.5
Cd	0	0	0	0.01952 (5)	0.5
Zn	0.5	0.5	0.5	0.01159 (3)
F1	0.125	0.125	0.125	0.0198 (2)
F2	0.125	0.125	0.41728 (12)	0.0267 (2)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Na	0.01952 (8)	0.01952 (8)	0.01952 (8)	−0.00344 (5)	−0.00344 (5)	−0.00344 (5)
Cd	0.01952 (8)	0.01952 (8)	0.01952 (8)	−0.00368 (7)	−0.00368 (7)	−0.00368 (7)
Zn	0.01159 (7)	0.01159 (7)	0.01159 (7)	−0.00036 (3)	−0.00036 (3)	−0.00036 (3)
F1	0.0198 (4)	0.0198 (4)	0.0198 (4)	0	0	0
F2	0.0250 (3)	0.0250 (3)	0.0302 (6)	−0.0131 (4)	0	0

Geometric parameters (Å, º)

Na—F1	2.2401	Cd—Na^ii	3.6581
Na—F1^i	2.2401	Cd—Na^ix	3.6581
Na—F2^ii	2.5176 (9)	Zn—F2^x	2.0197 (5)
Na—F2^iii	2.5176 (9)	Zn—F2^xi	2.0197 (5)
Na—F2^iv	2.5176 (9)	Zn—F2^xii	2.0197 (5)
Na—F2^v	2.5176 (9)	Zn—F2^xiii	2.0197 (5)
Na—F2^vi	2.5176 (9)	Zn—F2^xiv	2.0197 (5)
Na—F2^vii	2.5176 (9)	Zn—F2^xv	2.0197 (5)
Na—Na^viii	3.6581	Zn—Na^xvi	3.6581
Na—Cd^viii	3.6581	Zn—Na^xvii	3.6581
Na—Cd^ii	3.6581	Zn—Na^xviii	3.6581
Na—Cd^ix	3.6581	F1—F2^ii	3.0233 (13)
Cd—F1	2.2401	F2—F2^xix	3.0406 (13)
Cd—F1^i	2.2401	F2—F2^xx	2.6593 (3)
Cd—F2^ii	2.5176 (9)	F2—F2^xxi	2.6593 (3)
Cd—F2^iii	2.5176 (9)	F2—F2^xxii	3.0406 (13)
Cd—F2^iv	2.5176 (9)	F2—F2^xxiii	3.0406 (13)
Cd—F2^v	2.5176 (9)	F2—F2^xxiv	2.6593 (3)
Cd—F2^vi	2.5176 (9)	F2—F2^xxv	2.6593 (3)
Cd—F2^vii	2.5176 (9)	F2—F2	3.0406 (13)
Cd—Na^viii	3.6581
F1—Na—F1^i	180.0	F2^iii—Cd—F2^v	116.25 (1)
F1—Na—F2^iii	78.67 (2)	F2^iii—Cd—F2^vi	116.25 (1)
F1—Na—F2^ii	101.33 (2)	F2^iii—Cd—F2^vii	63.75 (1)
F1—Na—F2^iv	101.33 (2)	F1^i—Cd—F2^vii	78.67 (2)
F1—Na—F2^v	78.67 (2)	F2^x—Zn—F2^xi	180.0
F2^ii—Na—F2^iii	180.0	F2^x—Zn—F2^xiii	82.35 (3)
F1—Na—F2^vii	101.33 (2)	F2^x—Zn—F2^xii	97.65 (3)
F1—Na—F2^vi	78.67 (2)	F2^x—Zn—F2^xv	97.65 (3)
F2^ii—Na—F2^v	63.75 (1)	F2^x—Zn—F2^xiv	82.35 (3)
F2^ii—Na—F2^iv	116.25 (1)	F2^xi—Zn—F2^xiii	97.65 (3)
F1^i—Na—F2^ii	78.67 (2)	F2^xi—Zn—F2^xii	82.35 (3)
F1^i—Na—F2^iii	101.33 (2)	F2^xi—Zn—F2^xv	82.35 (3)
F2^ii—Na—F2^vi	63.75 (1)	F2^xi—Zn—F2^xiv	97.65 (3)
F2^iii—Na—F2^ii	180.0	F2^xii—Zn—F2^xiv	82.35 (3)
F1^i—Na—F2^v	101.33 (2)	F2^xii—Zn—F2^xv	97.65 (3)
F1^i—Na—F2^iv	78.67 (2)	F2^xii—Zn—F2^xiii	180.0
F2^iii—Na—F2^iv	63.75 (1)	Cd—F1—Cd^viii	109.471
F2^iii—Na—F2^v	116.25 (1)	Na—F1—Na^viii	109.471
F2^iii—Na—F2^vi	116.25 (1)	Na—F1—Na^ix	109.471
F2^iii—Na—F2^vii	63.75 (1)	Cd—F1—Cd^ix	109.471
F1^i—Na—F2^vii	78.67 (2)	Na—F1—Na^xxvi	109.471
F1—Na—F1^i	180.0	Cd—F1—Cd^xxvi	109.471
F1—Cd—F2^iii	78.67 (2)	Na^viii—F1—Na^ix	109.471
F1—Cd—F2^ii	101.33 (2)	Cd^viii—F1—Cd^ix	109.471
F1—Cd—F2^iv	101.33 (2)	Na^viii—F1—Na^xxvi	109.471
F1—Cd—F2^v	78.67 (2)	Cd^viii—F1—Cd^xxvi	109.471
F2^ii—Cd—F2^iii	180.0	Na^ix—F1—Na^xxvi	109.471
F1—Cd—F2^vii	101.33 (2)	Cd^ix—F1—Cd^xxvi	109.471
F1—Cd—F2^vi	78.67 (2)	Zn^xxvii—F2—Zn^xxviii	129.80 (6)
F2^ii—Cd—F2^v	63.75 (1)	Zn^xxvii—F2—Na^viii	106.946 (14)
F2^ii—Cd—F2^iv	116.25 (1)	Zn^xxvii—F2—Cd^viii	106.946 (14)
F1^i—Cd—F2^ii	78.67 (2)	Zn^xxvii—F2—Na^xxvi	106.946 (14)
F1^i—Cd—F2^iii	101.33 (2)	Zn^xxvii—F2—Cd^xxvi	106.946 (14)
F2^ii—Cd—F2^vi	63.75 (1)	Zn^xxviii—F2—Na^viii	106.946 (14)
F2^iii—Cd—F2^ii	180.0	Zn^xxviii—F2—Cd^viii	106.946 (14)
F1^i—Cd—F2^v	101.33 (2)	Zn^xxviii—F2—Na^xxvi	106.946 (14)
F1^i—Cd—F2^iv	78.67 (2)	Zn^xxviii—F2—Cd^xxvi	106.946 (14)
F2^iii—Cd—F2^iv	63.75 (1)

Symmetry codes: (i) −x, −y, −z; (ii) −y, x−1/4, z−1/4; (iii) y, −x+1/4, −z+1/4; (iv) −x, z−1/4, y−1/4; (v) x, −z+1/4, −y+1/4; (vi) −z+1/4, −x+1/4, y; (vii) z−1/4, x−1/4, −y; (viii) −y, x+1/4, z+1/4; (ix) −x+1/4, −y+1/4, z; (x) x+1/2, y+1/2, z; (xi) −x+1/2, −y+1/2, −z+1; (xii) z, x+1/2, y+1/2; (xiii) −z+1, −x+1/2, −y+1/2; (xiv) x+1/4, −z+1, y+1/4; (xv) −x+3/4, z, −y+3/4; (xvi) −y+1/2, x+1/4, z+3/4; (xvii) −y+1/2, x+3/4, z+1/4; (xviii) −x+1/4, −y+3/4, z+1/2; (xix) z−1/2, x, y+1/2; (xx) −z+1/2, −x, −y+1/2; (xxi) −x+1/2, z−1/4, y+1/4; (xxii) x, −z+3/4, −y+3/4; (xxiii) −z+3/4, −x+1/4, y+1/2; (xxiv) z−1/4, x+1/4, −y+1/2; (xxv) x−1/4, −z+1/2, y+1/4; (xxvi) y+1/4, −x, z+1/4; (xxvii) x−1/2, y−1/2, z; (xxviii) −x+3/4, −y+3/4, z.