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The structure of calcium chlorite, Ca(ClO2)2, has been refined from X-ray powder diffraction data using the Rietveld method. The compound crystallizes in the orthorhombic space group Ccca (Ccce), with Z = 4. The structure is based on separate layers parallel to the ac plane, consisting of calcium cations that are coordinated by chlorite anions; the O atoms form almost ideal square antiprisms. Within the layers, each anion bridges four metal cations. The Ca atoms are located on special positions of 222 symmetry, the Cl atoms lie on twofold axes and the O atoms are in general positions. The compound is isostructural with strontium chlorite, Sr(ClO2)2, and lead chlorite, Pb(ClO2)2.
Supporting information
Key indicators
- Powder X-ray study
- T = 293 K
- Mean (l-O) = 0.003 Å
- R factor = 0.000
- wR factor = 0.000
- Data-to-parameter ratio = 0.0
checkCIF/PLATON results
No syntax errors found
Alert level A
PLAT129_ALERT_4_A Unusual Space group Specified .................. CCCA(C
Alert level B
Crystal system given = orthorhombic
PLAT431_ALERT_2_B Short Inter HL..A Contact Cl .. O .. 2.85 Ang.
PLAT431_ALERT_2_B Short Inter HL..A Contact Cl .. O .. 2.85 Ang.
Alert level C
REFI023_ALERT_1_C _refine_diff_density_max is missing
Maximum value of final difference map (e A-3).
The following tests will not be performed
DIFMN_01,DIFMX_01,DIFMX_02
REFI024_ALERT_1_C _refine_diff_density_min is missing
Minimum value of final difference map (e A-3).
The following tests will not be performed
DIFMN_01,DIFMN_02,DIFMN_03
PLAT041_ALERT_1_C Calc. and Rep. SumFormula Strings Differ .... ?
PLAT430_ALERT_2_C Short Inter D...A Contact O .. O .. 2.88 Ang.
PLAT799_ALERT_4_C Numeric Label on Displacement Par. Record ...... ?
1 ALERT level A = In general: serious problem
2 ALERT level B = Potentially serious problem
5 ALERT level C = Check and explain
0 ALERT level G = General alerts; check
3 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
3 ALERT type 2 Indicator that the structure model may be wrong or deficient
0 ALERT type 3 Indicator that the structure quality may be low
2 ALERT type 4 Improvement, methodology, query or suggestion
Data collection: APD1700 Software (Philips, 1989); cell refinement: FULLPROF2k (Rodriguez-Carvajal, 2004); program(s) used to refine structure: FULLPROF2k; molecular graphics: BS (Ozawa & Kang, 2004); software used to prepare material for publication: WINPLOTR (Roisnel & Rodriguez-Carvajal, 2005).
calcium chlorate(III)
top
Crystal data top
Ca(ClO2)2 | Z = 4 |
Mr = 174.98 | Dx = 2.798 Mg m−3 |
Orthorhombic, Ccca(Ccce) | Cu Kα radiation, λ = 1.54178 Å |
a = 5.7434 (7) Å | T = 293 K |
b = 12.6002 (9) Å | Particle morphology: plate-like |
c = 5.7405 (7) Å | white |
V = 415.43 (8) Å3 | flat_sheet, 10 × 10 mm |
Data collection top
Philips PW1700 powder diffractometer | Data collection mode: reflection |
Radiation source: sealed X-ray tube | Scan method: step |
Graphite monochromator | 2θmin = 5.041°, 2θmax = 145.041°, 2θstep = 0.020° |
Specimen mounting: drifted powder on standard quartz sample holder | |
Refinement top
Least-squares matrix: full | 31 parameters |
Rp = 0.127 | 1 restraint |
Rwp = 0.145 | Weighting scheme based on measured s.u.'s w = 1/[σ2(Yi)] |
Rexp = 0.080 | (Δ/σ)max = 0.01 |
RBragg = 0.043 | Background function: six-coefficients polinomial function |
7001 data points | Preferred orientation correction: Icorr = Iobs[G2+(1 – G2)exp(G1α2)], where α is the acute angle
between the scattering vector and the normal to the crystallites, G1 =
-2.69(2), G2 = 0.102(1), axis [010], (Rietveld, 1969) |
Profile function: split pseudo-Voigt | |
Special details top
Experimental. The experimental data were collected with Cu K? radiation (λ1=1.54060 Å,
λ2=1.54439 Å) on a Philips PW1700 automatic diffractometer with Si as
external standard. |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
Ca | 0.00000 | 0.25000 | 0.25000 | 0.0054 (6)* | |
Cl | 0.50000 | 0.08227 (11) | 0.25000 | 0.0172 (4)* | |
O | 0.3337 (6) | 0.14953 (10) | 0.0865 (6) | 0.0321 (9)* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
? | ? | ? | ? | ? | ? | ? |
Geometric parameters (Å, º) top
Ca—O | 2.481 (3) | Cl—O | 1.585 (3) |
Ca—Oi | 2.499 (3) | | |
| | | |
O—Cl—Oii | 115.3 (3) | | |
Symmetry codes: (i) −x+1/2, y, z+1/2; (ii) −x+1, y, −z+1/2. |
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