inorganic compounds
The structure of strontium chlorite, Sr(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 strontium 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 Sr 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 calcium chlorite, Ca(ClO2)2, and lead chlorite, Pb(ClO2)2.
Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536805034161/wm6101sup1.cif | |
Rietveld powder data file (CIF format) https://doi.org/10.1107/S1600536805034161/wm6101IIsup2.rtv |
Computing details top
Data collection: APD1700 Software (Philips, 1989); cell refinement: FULLPROF2k (Rodriguez-Carvajal, 2004); program(s) used to refine structure: FULLPROF2k; software used to prepare material for publication: WINPLOTR (Roisnel & Rodriguez-Carvajal, 2005).
strontium chlorate(III) top
Crystal data top
Sr(ClO2)2 | Z = 4 |
Mr = 222.52 | Dx = 3.242 Mg m−3 |
Orthorhombic, Ccca(Ccce) | CuKα radiation, λ = 1.54178 Å |
a = 5.9799 (12) Å | T = 293 K |
b = 12.7519 (16) Å | Particle morphology: plate-like |
c = 5.9787 (12) Å | white |
V = 455.92 (11) 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 = 4.819°, 2θmax = 144.819°, 2θstep = 0.020° |
Specimen mounting: drifted powder on standard quartz sample holder |
Refinement top
Least-squares matrix: full | 28 parameters |
Rp = 0.136 | 1 restraint |
Rwp = 0.165 | Weighting scheme based on measured s.u.'s w = 1/[σ2(Yi)] |
Rexp = 0.055 | (Δ/σ)max = 0.01 |
RBragg = 0.057 | 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 = -0.54(5), G2 = 0.29(3), axis [010], (Rietveld, 1969) |
Profile function: split pseudo-Voigt |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
x | y | z | Uiso*/Ueq | ||
Sr | 0.00000 | 0.25000 | 0.25000 | 0.0105 (4)* | |
Cl | 0.50000 | 0.07460 (16) | 0.25000 | 0.0215 (7)* | |
O | 0.3443 (10) | 0.1447 (4) | 0.1005 (10) | 0.050 (2)* |
Geometric parameters (Å, º) top
Sr—O | 2.615 (6) | Cl—O | 1.570 (6) |
Sr—Oi | 2.657 (6) | ||
O—Cl—Oii | 110.6 (6) |
Symmetry codes: (i) −x+1/2, y, z+1/2; (ii) −x+1, y, −z+1/2. |