research papers
The volcanic exhalation product chlorartinite, [Mg2(CO3)(H2O)(OH)]Cl·H2O, has recently been found to be a minor, and in some samples a major, component of magnesia floors for industrial use. In order to be able to perform quantitative phase analysis using the Rietveld method, its crystal structure was determined from high-resolution synchrotron powder diffraction data by the global optimization technique of simulated annealing and Rietveld refinement. The final Rp and Rwp values are 5.23% and 6.56%, respectively. Chlorartinite crystallizes in the rhombohedral space group R3c (No. 161), with a = 23.14422 (16) Å, c = 7.22333 (5) Å, V = 3350.84 (5) Å3, Z = 18. The building units of chlorartinite consist of MgO6 octahedra forming 15-membered puckered rings which are interconnected by CO3 triangular moieties. The rings are stacked to form a honeycomb-like three-dimensional framework structure with large isolated channels. Within the channels, free chlorine atoms and disordered water molecules are located.
Keywords: chlorartinite; magnesia screed; quantitative phase analysis; inclusion compounds; channel structure.
Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0021889806032109/db5003sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0021889806032109/db5003sup2.hkl | |
Rietveld powder data file (CIF format) https://doi.org/10.1107/S0021889806032109/db5003sup3.rtv | |
Rietveld powder data file (CIF format) https://doi.org/10.1107/S0021889806032109/db5003sup4.rtv |
Computing details top
Magnesium chloride aqua carbonete hydrate top
Crystal data top
H5CO6Mg2Cl | Z = 18 |
Mr = 197.11 | Dx = 1.758 Mg m−3 |
Trigonal, R3c | Synchrotron radiation, λ = 0.64889 Å |
a = 23.14422 (16) Å | T = 295 K |
c = 7.22333 (5) Å | ?, ? × ? × ? mm |
V = 3350.84 (5) Å3 |
Crystal data top
H5CO6Mg2Cl | V = 3350.84 (5) Å3 |
Mr = 197.11 | Z = 18 |
Trigonal, R3c | Synchrotron radiation, λ = 0.64889 Å |
a = 23.14422 (16) Å | T = 295 K |
c = 7.22333 (5) Å | ?, ? × ? × ? mm |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
x | y | z | Uiso*/Ueq | Occ. (<1) | |
Cl1 | 0.15058 (15) | 0.19895 (14) | −0.1824 (9) | 0.0308 (12)* | |
Mg1 | 0.2847 (2) | 0.1193 (2) | −0.0737 (8) | 0.0209 (15)* | |
Mg2 | 0.2800 (2) | 0.3149 (2) | 0.3367 (9) | 0.0184 (15)* | |
O1 | 0.1859 (4) | 0.0937 (4) | −0.0918 (14) | 0.074 (3)* | |
O2 | 0.2959 (3) | 0.1845 (3) | 0.1532 (9) | 0.0136 (15)* | |
O3 | 0.3207 (4) | 0.2257 (3) | −0.1268 (7) | 0.0136 (15)* | |
O4 | 0.3189 (4) | 0.2873 (3) | 0.1151 (8) | 0.0136 (15)* | |
O5 | 0.2660 (4) | 0.2374 (4) | 0.5035 (11) | 0.003 (3)* | |
O6 | 0.1885 (3) | 0.2766 (3) | 0.1732 (12) | 0.029 (3)* | |
O7 | 0.0113 (18) | 0.0704 (13) | −0.035 (4) | 0.144 (12)* | 0.4 |
O8 | 0.0078 (12) | 0.0846 (9) | −0.246 (2) | 0.141 (8)* | 0.6 |
C1 | 0.3046 (2) | 0.2308 (3) | 0.0423 (7) | 0.0136 (15)* |
Geometric parameters (Å, º) top
Mg1—O1 | 2.058 (8) | Mg2—O4 | 2.149 (7) |
Mg1—O2 | 2.154 (7) | Mg2—O5 | 2.048 (8) |
Mg1—O2 | 2.010 (6) | Mg2—O5 | 2.140 (8) |
Mg1—O3 | 2.204 (7) | Mg2—O6 | 2.188 (9) |
Mg1—O5 | 1.999 (8) | O2—C1 | 1.2700 (5) |
Mg1—O6 | 2.280 (8) | O3—C1 | 1.2999 (5) |
Mg2—O3 | 2.071 (8) | O4—C1 | 1.2900 (5) |
Mg2—O4 | 2.087 (7) | ||
O1—Mg1—O2 | 88.7 (3) | O4—Mg2—O6 | 86.6 (3) |
O1—Mg1—O2 | 95.0 (4) | O4—Mg2—O5 | 84.8 (3) |
O1—Mg1—O3 | 93.2 (4) | O4—Mg2—O5 | 89.6 (3) |
O1—Mg1—O5 | 95.1 (4) | O4—Mg2—O6 | 168.3 (4) |
O1—Mg1—O6 | 168.9 (4) | O5—Mg2—O5 | 174.4 (3) |
O2—Mg1—O2 | 146.6 (3) | O5—Mg2—O6 | 105.4 (3) |
O2—Mg1—O3 | 60.23 (15) | O5—Mg2—O6 | 80.2 (3) |
O2—Mg1—O5 | 114.3 (3) | Mg1—O2—Mg1 | 129.4 (3) |
O2—Mg1—O6 | 83.5 (3) | Mg1—O2—C1 | 91.4 (3) |
O2—Mg1—O3 | 86.4 (3) | Mg1—O2—C1 | 138.9 (4) |
O2—Mg1—O5 | 98.5 (4) | Mg1—O3—Mg2 | 144.6 (3) |
O2—Mg1—O6 | 95.9 (4) | Mg1—O3—C1 | 88.4 (3) |
O3—Mg1—O5 | 169.9 (4) | Mg2—O3—C1 | 126.3 (6) |
O3—Mg1—O6 | 89.8 (3) | Mg2—O4—Mg2 | 92.3 (2) |
O5—Mg1—O6 | 81.0 (3) | Mg2—O4—C1 | 133.8 (4) |
O3—Mg2—O4 | 175.0 (4) | Mg2—O4—C1 | 131.4 (3) |
O3—Mg2—O4 | 96.0 (3) | Mg1—O5—Mg2 | 124.1 (4) |
O3—Mg2—O5 | 89.4 (3) | Mg1—O5—Mg2 | 101.0 (3) |
O3—Mg2—O5 | 91.8 (3) | Mg2—O5—Mg2 | 93.7 (3) |
O3—Mg2—O6 | 90.0 (3) | Mg1—O6—Mg2 | 91.4 (3) |
O4—Mg2—O4 | 86.8 (2) | O2—C1—O3 | 116.65 (18) |
O4—Mg2—O5 | 95.0 (3) | O2—C1—O4 | 116.76 (17) |
O4—Mg2—O5 | 84.1 (3) | O3—C1—O4 | 122.33 (17) |
Experimental details
Crystal data | |
Chemical formula | H5CO6Mg2Cl |
Mr | 197.11 |
Crystal system, space group | Trigonal, R3c |
Temperature (K) | 295 |
a, c (Å) | 23.14422 (16), 7.22333 (5) |
V (Å3) | 3350.84 (5) |
Z | 18 |
Radiation type | Synchrotron, λ = 0.64889 Å |
Specimen shape, size (mm) | ?, ? × ? × ? |
Data collection | |
Diffractometer | ? |
Specimen mounting | ? |
Data collection mode | ? |
Scan method | ? |
2θ values (°) | 2θmin = ? 2θmax = ? 2θstep = ? |
Refinement | |
R factors and goodness of fit | Rp = 0.052, Rwp = 0.066, Rexp = 0.065, R(F2) = 0.11080, χ2 = NOT FOUND |
No. of data points | ? |
No. of parameters | ? |
No. of restraints | ? |