inorganic compounds
Potassium calcium fluoride carbonate, KCaF(CO3), has been synthesized and its structure solved from X-ray powder diffraction data. The K, Ca, F and C atoms lie at sites with imposed symmetry and the unique O atom has imposed mm site symmetry. The compound consists of Ca-F-Ca chains parallel to the c axis and planar CO3 groups perpendicular to the c axis, the corners of the hexagonal cell being occupied by K+ ions. The compound is not a solid solution, since the structure differs from those of both KF and CaCO3.
Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536804005069/wn6225sup1.cif | |
Rietveld powder data file (CIF format) https://doi.org/10.1107/S1600536804005069/wn6225Isup2.rtv |
Computing details top
Data collection: Rint2400 (Rigaku Corporation, 1993); cell refinement: Highscore1.0b (Philips Electronics, 2002); data reduction: Highscore1.0b (Philips Electronics, 2002); program(s) used to solve structure: SHEXLS97 (Sheldrick, 1997); program(s) used to refine structure: FULLPROF (Rodriguez-Carvajal, 2003); molecular graphics: Balls & Sticks (Kang & Ozawa, 2003).
potassium calcium flurine-carbonate top
Crystal data top
KCaF(CO3) | Dx = 2.615 Mg m−3 |
Mr = 158.17 | Melting point: 774.0 K |
Hexagonal, P6m2 | CuKα1, CuKα2 radiation, λ = 1.540562, 1.544390 Å |
Hall symbol: P -6 2 | T = 295 K |
a = 5.10093 (7) Å | Particle morphology: plate-like |
c = 4.45510 (7) Å | white |
V = 100.39 (1) Å3 | flat_sheet, 15 × 35 mm |
Z = 1 | Specimen preparation: Prepared at 873 K |
F(000) = 78 |
Data collection top
Rint2400 diffractometer | Data collection mode: reflection |
Radiation source: rotating-anode x-ray tube | Scan method: step |
Curved graphite monochromator | 2θmin = 10°, 2θmax = 135°, 2θstep = 0.02° |
Specimen mounting: packed powder pellet |
Refinement top
Refinement on Inet | Profile function: pseudo-Voigt |
Least-squares matrix: full with fixed elements per cycle | 26 parameters |
Rp = 0.080 | 1/Yi |
Rwp = 0.128 | (Δ/σ)max = 0.01 |
Rexp = 0.056 | Background function: square polynomial for each range |
6251 data points | Preferred orientation correction: Icorr = Iobs[G2+(1-G2)exp(G1a2)], axis (001), (March, 1932) |
Excluded region(s): none |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
x | y | z | Uiso*/Ueq | ||
K | 0 | 0 | 0 | 0.0126 (6)* | |
C | 0.66667 | 0.33333 | 0.5 | 0.018 (2)* | |
Ca | 0.33333 | 0.66667 | 0.5 | 0.0100 (6)* | |
O | 0.8120 (3) | 0.1880 (3) | 0.5 | 0.0129* | |
F | 0.33333 | 0.66667 | 0 | 0.0196 (1)* |
Geometric parameters (Å, º) top
K—Oi | 2.779 (1) | C—Oix | 1.284 (1) |
K—Oii | 2.779 (1) | C—Ovi | 1.284 (1) |
K—Oiii | 2.779 (1) | Ca—Oii | 2.557 (1) |
K—Oiv | 2.779 (1) | Ca—Ox | 2.557 (1) |
K—Ov | 2.779 (1) | Ca—Oxi | 2.557 (1) |
K—Ovi | 2.779 (1) | Ca—Oix | 2.557 (1) |
K—Fvii | 2.9450 (1) | Ca—Ovi | 2.557 (1) |
K—Fviii | 2.9450 (1) | Ca—Oxii | 2.557 (1) |
K—F | 2.9450 (1) | Ca—F | 2.2275 (1) |
C—O | 1.284 (1) | Ca—Fxiii | 2.2275 (1) |
O—C—Oix | 120 | Oix—C—Ovi | 120 |
O—C—Ovi | 120 |
Symmetry codes: (i) x−1, y, z−1; (ii) x−1, y, z; (iii) −y, x−y−1, z−1; (iv) −y, x−y−1, z; (v) −x+y+1, −x+1, z−1; (vi) −x+y+1, −x+1, z; (vii) x−1, y−1, z; (viii) x, y−1, z; (ix) −y+1, x−y, z; (x) x, y+1, z; (xi) −y, x−y, z; (xii) −x+y+1, −x+2, z; (xiii) x, y, z+1. |