The crystal structure of schairerite and its relationship to sulphohalite

1975 ◽  
Vol 40 (310) ◽  
pp. 131-139 ◽  
Author(s):  
L. Fanfani ◽  
A. Nunzi ◽  
P. F. Zanazzi ◽  
A. R. Zanzari ◽  
C. Sabelli
Keyword(s):  
Crystal Structure ◽  
Diffraction Data ◽  
Hexagonal Lattice ◽  
Three Dimensional ◽  
Chemical Formula ◽  
X Ray Diffraction ◽  
Cell Content ◽  
X Ray ◽  
Structural Framework ◽  
Unequal Number

SummaryThe crystal structure of schairerite from Searles Lake, California, has been determined employing X-ray diffraction data collected on a single-crystal diffractometer. The crystal structure was refined by least-squares methods employing isotropic thermal parameters to a final R index of 0·07 for 2536 independent observed reflections. The cell content is 3[Na21(SO4)7F6Cl]. The space group is P31m with a 12·197 A and c 19·259 Å. Schairerite exhibits a marked sub-cell (a 7·042 Å, the same c axis and P3m1 symmetry), which may be related to the unit cell of sulphohalite when described in a hexagonal lattice.The crystal structure of schairerite may be considered as consisting of seven sheets of Na+ ions perpendicular to the c axis. These sheets are connected to each other .building up a three-dimensional framework. The Na+ ions in these sheets are arranged in an array built up of hexagons and triangles. Sulphur atoms lie in the sheets at the centres of each hexagon, the halogen atoms lying between the sheets midway between the centres of two triangles. A comparison with sulphohalite shows that the close lattice analogies may be related to a similar atomic arrangement. Apart from the differences in chemical formula (F:C1 ratio 1:1 in sulphohalite), the main difference in the structural framework consists of the unequal number of Na+ sheets (six in sulphohalite) and in the SO42− tetrahedra orientation.

The crystal structure of galeite, Na15(SO4)5F4Cl

1975 ◽  
Vol 40 (312) ◽  
pp. 357-361 ◽  
Author(s):  
L. Fanfani ◽  
A. Nunzi ◽  
P. F. Zanazzi ◽  
A. R. Zanzari
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Least Squares ◽  
Diffraction Data ◽  
Three Dimensional ◽  
Thermal Parameters ◽  
X Ray Diffraction ◽  
Cell Content ◽  
X Ray ◽  
Structure Factors

SummaryThe crystal structure of galeite from Searles Lake (California) has been determined by means of X-ray diffraction data on a single crystal. A possible structure was derived from that of schairerite on the basis of chemical and lattice analogies and was confirmed by comparison of the observed diffractometric structure factors with the calculated ones. The refinement was performed by least-squares methods employing isotropic thermal parameters and assuming that atoms related by translational pseudosymmetry exhibit equal thermal parameters. The final R value is 0·09. The cell content is 3[Na15(SO4)5F4Cl]; the space group is P31m The lattice dimensions are a 12·197(4)Å, c 13·955(10) Å The marked subcell has P3m1 symmetry and a 7·042Å, c 13·955 Å. The crystal structure of galeite consists of a three-dimensional framework, formed by coordination octahedra around Na+ ions, including tetrahedral holes with sulphur atoms at the centres. The three-dimensional framework can be considered built up by five octahedral sheets (seven sheets can be recognized in schairerite and six in sulphohalite). The very close analogies occurring in the structures of galeite and schairerite are discussed.

The crystal structure of gersdorffite (III), a distorted and disordered pyrite structure

1968 ◽  
Vol 36 (283) ◽  
pp. 940-947 ◽  
Author(s):  
P. Bayliss ◽  
N. C. Stephenson
Keyword(s):  
Crystal Structure ◽  
Metal Atom ◽  
Diffraction Data ◽  
Three Dimensional ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Partially Ordered ◽  
The Ideal

SummaryThe crystal structure of gersdorffite (III) has been examined with three-dimensional Weissenberg X-ray diffraction data. The unit cell is isometric with a 5·6849 ± 0·0003 Å, space group PI, and four formula units per cell. This structure has the sulphur and arsenic atoms equally distributed over the non-metal atom sites of pyrite. All atoms show significant random displacements from the ideal pyrite positions to produce triclinic symmetry, which serves to distinguish this mineral from a disordered cubic gersdorffite (II) and a partially ordered cubic gersdorffite (I). Factors responsible for the atomic distortions are discussed.

Al analogue of chayesite from a lamproite of Cancarix, SE Spain, and its crystal structure

2020 ◽  
Vol 196 (3) ◽  
pp. 193-198
Author(s):  
Natalia V. Zubkova ◽  
Nikita V. Chukanov ◽  
Christof Schäfer ◽  
Konstantin V. Van ◽  
Igor V. Pekov ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Diffraction Data ◽  
Empirical Formula ◽  
Structure Refinement ◽  
Crystal Chemical ◽  
Chemical Formula ◽  
Crystal Chemical Formula ◽  
X Ray Diffraction ◽  
Se Spain ◽  
X Ray

Al analogue of chayesite (with Al > Fe3+) was found in a lamproite from Cancarix, SE Spain. The mineral forms green thick-tabular crystals up to 0.4 mm across in cavities. The empirical formula derived from EMP measurements and calculated on the basis of 17 Mg + Fe + Al + Si apfu is (K0.75 Na0.20 Ca0.11)Mg3.04 Fe0.99 Al1.18 Si11.80 O30. The crystal structure was determined from single crystal X-ray diffraction data ( R = 2.38%). The mineral is hexagonal, space group P 6/ mcc, a = 10.09199(12), c = 14.35079(19) Å, V = 1265.78(3) Å3, Z = 2. Fe is predominantly divalent. Al is mainly distributed between the octahedral A site and the tetrahedral T 2 site. The crystal chemical formula derived from the structure refinement is C (K0.73 Na0.16 Ca0.11)B (Na0.02)4 A(Mg0.42 Al0.29 Fe0.29)2 T 2(Mg0.71 Fe0.16 Al0.13)3 T 1(Si0.985 Al0.015)12 O30.

The crystal structure of, and the bismuth-copper distribution in synthetic cuprobisrauthite

1975 ◽  
Vol 142 (3-4) ◽  
Author(s):  
T. Ozawa ◽  
W. Nowacki
Keyword(s):  
Crystal Structure ◽  
Diffraction Data ◽  
Three Dimensional ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Copper Distribution

AbstractThe crystal structure of synthetic cuprobismuthite has been determined using three-dimensional x-ray diffraction data. The space group isAll atoms he on mirror planes of the space group at

Crystal structure of low-cristobalite-type Al0.5Ga0.5PO4: A combined Rietveld refinement of neutron and X-ray diffraction data

2005 ◽  
Vol 20 (3) ◽  
pp. 207-211 ◽  
Author(s):  
S. N. Achary ◽  
A. K. Tyagi ◽  
S. K. Kulshreshtha ◽  
O. D. Jayakumar ◽  
P. S. R. Krishna ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Diffraction Data ◽  
Three Dimensional ◽  
Crystal Structure Analysis ◽  
Tetrahedral Coordination ◽  
X Ray Diffraction ◽  
Rietveld Refinements ◽  
X Ray ◽  
Cell Parameters ◽  
Bond Lengths

The low-cristobalite-type modification of Al0.5Ga0.5PO4 is prepared by annealing the amorphous precipitate of stoichiometric phosphate at 1300 °C. The phase purity of the sample is ascertained by powder X-ray diffraction. The crystal structure is refined by Rietveld refinements of the neutron and X-ray diffraction data of the polycrystalline powder. This compound crystallizes in an orthorhombic lattice with unit cell parameters, a=7.0295(8), b=7.0132(8), and c=6.9187(4) Å, V=341.08(6) Å3, Z=4 (Space group C 2221, No. 20). The crystal structure analysis reveals the random distribution of the Al3+ and Ga3+ having tetrahedral coordination with typical M–O (M=Al3+:Ga3+) bond lengths as 1.74 Å. Similarly, the P5+ have tetrahedral coordination with typical P–O bond lengths 1.52–1.54 Å. The Mo4 and PO4 tetraheda are linked by common corners forming a three-dimensional framework lattice. The details of the crystal structure are presented in this paper.

scholarly journals Crystal structure and revision of the chemical formula of georgiadesite, Pb4(AsO3)Cl4(OH)

2000 ◽  
Vol 64 (5) ◽  
pp. 879-884 ◽  
Author(s):  
M. Pasero ◽  
D. Vacchiano
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Structural Study ◽  
Diffraction Data ◽  
Chemical Formula ◽  
X Ray Diffraction ◽  
X Ray ◽  
Trigonal Prisms

AbstractThe crystal structure of the rare secondary lead mineral georgiadesite has been solved from single-crystal X-ray diffraction data (R = 0.071). The structure can be visualized in terms of alternating puckered (100) layers of [Pbϕ6] octahedra and [Pbϕ8] bicapped trigonal prisms (ϕ = generic anion). Lead also occurs in irregular, lopsided polyhedra. This structural study shows unambiguously that arsenic occurs as As3+ and not as As5+. The chemical formula of georgiadesite has therefore been revised, on structural grounds, to Pb4(AsO3)Cl4(OH).

Über zwei Modifikationen von "Tl2Cl3"-valenzgemischten Thallium(I)-hexahalogenothallaten(III) Tl3 [TlCl6] / On Two Modifications of "Tl2Cl3"-Mixed Valence Thallium(I)-hexahalogenothallates(III)

1980 ◽  
Vol 35 (11) ◽  
pp. 1366-1372 ◽  
Author(s):  
Reinhild Böhme ◽  
Jörg Rath ◽  
Bernd Grunwald ◽  
Gerhard Thiele
Keyword(s):  
Crystal Structure ◽  
Raman Spectra ◽  
Diffraction Data ◽  
Mixed Valence ◽  
Three Dimensional ◽  
The Other ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cell Parameters ◽  
Thallium Chloride

The mixed valence thallium chloride "Tl2Cl3" is polymorphous. Raman spectra and comparable lattice translations suggest similar structures of both modifications. The crystal structure of the rhombic α-Tl2Cl3 crystallizing in yellow, needle-shaped crystals, has been determined from three-dimensional X-ray diffraction data. The unit cell with cell parameters a= 1474.8(5) pm, b - 2508.7(6) pm and c = 1267.6(2) pm contains 16 formula units distributed on 24 independent atom positions. The compound is a mixed valence thallium(I)-hexachlorothallate(III) Tl3[TlCl6] because three of the nine independent Tl atoms are surrounded octahedrally by CI atoms in distances of 250-265 pm, while the other Tl atoms have seven, eight or nine CI neighbours variing between 306 and 383 pm.β-Tl3[TlCl6] forms pale yellow thin platelets and crystallizes monoclinic with cell parameters a = 2549.4(13) pm, 6 = 1469.9(8) pm, c = 1308.5(12) pm and β = 108.58°.

Crystal structure of cesium methylsulfonate, CsCH3SO3

1967 ◽  
Vol 45 (12) ◽  
pp. 1385-1390 ◽  
Author(s):  
J. K. Brandon ◽  
I. D. Brown
Keyword(s):  
Crystal Structure ◽  
Diffraction Data ◽  
Barium Sulfate ◽  
Three Dimensional ◽  
Thermal Motion ◽  
X Ray Diffraction ◽  
Methyl Group ◽  
Space Group ◽  
X Ray ◽  
Cesium Ion

Cesium methylsulfonate, CsCH3SO3, crystallizes in space group Pnma with a = 9.526, b = 6.264, and c = 8.692 Å. Three-dimensional X-ray diffraction data have been collected photographically and refined to give a weighted agreement index (R) of 0.12. The structure is related to, but is not identical with, that of the isoelectronic compound barium sulfate. The CH3SO3− ion has C3v symmetry within the accuracy of this analysis, with S—O = 1.47 ± 0.02, S—C = 1.85 ± 0.04 Å (corrected for thermal motion), O—S—O = 112 ± 1°, and O—S—C = 107 ± 2°. The cesium ion is surrounded by nine oxygen atoms (Cs—O between 3.12 and 3.35 Å) and one methyl group (Cs—C = 3.77 Å).

Crystal structure and spectra of the mixed-ligands complex 1-(2-thenoyl)-2-(2,2′-dipyridyl methylene)hydrazino-acetato lead (II)

1994 ◽  
Vol 209 (12) ◽  
Author(s):  
P. C. Christidis ◽  
I. A. Tossidis ◽  
C. A. Hondroudis
Keyword(s):  
Crystal Structure ◽  
Diffraction Data ◽  
Title Compound ◽  
Three Dimensional ◽  
X Ray Diffraction ◽  
Triclinic Space Group ◽  
Space Group ◽  
X Ray ◽  
Mixed Ligands

AbstractThe crystal structure of the title compound has been determined from three-dimensional X-ray diffraction data. The crystals are triclinic, space group

Crystal structure of 9-Oxofluorene-4-carboxylic acid

1981 ◽  
Vol 34 (5) ◽  
pp. 1143 ◽  
Author(s):  
CHL Kennard ◽  
G Smith ◽  
GF Katekar
Keyword(s):  
Crystal Structure ◽  
Carboxylic Acid ◽  
Diffraction Data ◽  
Three Dimensional ◽  
Direct Methods ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
A Cell

The crystal structure of 9-oxofluorene-4-carboxylic acid has been determined by direct methods using three-dimensional X-ray diffraction data, and refined to R0·068 for 1323 'observed' reflections. Crystals are monoclinic, space group P21/c with 24 in a cell of dimensions a 3·843(3), b 7·986(5), c 3269(2) �, β 96·64(4)�. The molecules form centrosymmetric hydrogen-bonded cyclic dimers [O···O 2·642(3) �] with the plane of the carboxylic acid making an angle of 26·5� with that of the 9-oxofluorene group. Stacks of molecules form down the a axis with 3.843 �. separation.

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