scholarly journals Crystal structure and revised chemical formula for burckhardtite, Pb2(Fe3+Te6+)[AlSi3O8]O6: a double-sheet silicate with intercalated phyllotellurate layers

2014 ◽  
Vol 78 (7) ◽  
pp. 1763-1773 ◽  
Author(s):  
Andrew G. Christy ◽  
Anthony R. Kampf ◽  
Stuart J. Mills ◽  
Robert M. Housley ◽  
Brent Thorne
Keyword(s):  
Crystal Structure ◽  
Chemical Formula ◽  
Unit Cell Parameters ◽  
Cell Parameters ◽  
Raman Spectroscopic ◽  
New Findings ◽  
Sheet Silicate ◽  
Symmetry Structure ◽  
The Ideal

AbstractThe crystal structure of burckhardite from the type locality, Moctezuma, Sonora, Mexico, has been refined to R1 = 0.0362 and wR2 = 0.0370 for 215 reflections with I > 2σ(I). Burckhardtite is trigonal, space group P3̄ 1m, with the unit-cell parameters a = 5.2566(5) Å , c = 13.0221(10) Å , V = 311.62(5) Å3 and Z = 1 for the ideal formula unit Pb2(Fe3+Te6+)[AlSi3O8]O6. There is no long-range order of (Fe3+, Te6+) or (Al3+, Si4+). New microprobe data were used to estimate site scattering factors, and Raman spectroscopic data showed no evidence of O–H stretching bands. Burckhardtite is not closely related to the micas, as supposed previously, but is a double-sheet silicate in which the aluminosilicate anion resembles that of minerals such as cymrite and kampfite. The [(Fe3+Te6+)O6]3– part of the structure is not bonded directly to the aluminosilicate layer, but forms a discrete anionic phyllotellurate layer that alternates with the [AlSi3O8]– double sheets. Similar phyllotellurate layers are known from several synthetic phases. In burckhardtite, Pb2+ cations intercalate between phyllosilicate and phyllotellurate layers, forming a Pb2[FeTeO6] module that is topologically similar to a slab of the structure of rosiaite, Pb[Sb2O6]. The crystal symmetry, structure, classification as a double-sheet silicate and chemical formula, including the determination of the 6+ valence of Te and absence of essential H2O, are all new findings for the mineral.

Weissite from Gambatesa mine, Val Graveglia, Liguria, Italy: occurrence, composition and determination of the crystal structure

2013 ◽  
Vol 77 (4) ◽  
pp. 475-483 ◽  
Author(s):  
L. Bindi ◽  
C. Carbone ◽  
D. Belmonte ◽  
R. Cabella ◽  
R. Bracco
Keyword(s):  
Crystal Structure ◽  
Vickers Hardness ◽  
Crystal Chemical ◽  
Chemical Formula ◽  
Unit Cell Parameters ◽  
Cell Parameters ◽  
Black Streak ◽  
Pure Metals ◽  
Complex Crystal

AbstractWeissite, Cu2–xTe (x ≈ 0.21), a very rare copper telluride, occurs in a sample from the Gambatesa mine, Val Graveglia, Liguria, Italy, where it occurs as purplish black anhedral grains up to 0.1 mm in length and shows a black streak. No cleavage is observed and the Vickers hardness (VHN100) is 142 kg/mm2. Weissite is dark bluish black, weakly pleochroic, and moderately anisotropic in bluish tints. Reflectance percentages in air for Rmin and Rmax are 37.0, 38.4 (471.1 nm), 33.2, 34.2 (548.3 nm), 31.2, 32.1 (586.6 nm), and 28.6, 31.0 (652.3 nm), respectively.Weissite is trigonal and belongs to the space group P3m1 with the following unit-cell parameters: a = 8.3124(7) Å, c = 21.546(1) Å, V = 1289.3(2) Å3, and Z = 24. Electron microprobe analyses gave the chemical formula (Cu1.62Ag0.04Au0.04Fe0.04Sb0.04)Σ=1.78(Te0.96S0.02Se0.02). The crystal structure has been solved and refined to R = 1.95%. It consists of Cu and Te polyhedra forming complex crystal-chemical environments as is typical of many intermetallic compounds. The exceedingly short bond distances observed among the metals are discussed in relation to other copper tellurides and pure metals.

scholarly journals The crystal structure of alstonite, BaCa(CO3)2: an extraordinary example of ‘hidden’ complex twinning in large single crystals

2020 ◽  
Vol 84 (5) ◽  
pp. 699-704
Author(s):  
Luca Bindi ◽  
Andrew C. Roberts ◽  
Cristian Biagioni
Keyword(s):  
Crystal Structure ◽  
Single Crystals ◽  
Structure Determination ◽  
Unit Cell ◽  
Crystal Structure Determination ◽  
Unit Cell Parameters ◽  
Space Group ◽  
Cell Parameters ◽  
Structure Determinations

AbstractAlstonite, BaCa(CO3)2, is a mineral described almost two centuries ago. It is widespread in Nature and forms magnificent cm-sized crystals. Notwithstanding, its crystal structure was still unknown. Here, we report the crystal-structure determination of the mineral and discuss it in relationship to other polymorphs of BaCa(CO3)2. Alstonite is trigonal, space group P31m, with unit-cell parameters a = 17.4360(6), c = 6.1295(2) Å, V = 1613.80(9) Å3 and Z = 12. The crystal structure was solved and refined to R1 = 0.0727 on the basis of 4515 reflections with Fo > 4σ(Fo) and 195 refined parameters. Alstonite is formed by the alternation, along c, of Ba-dominant and Ca-dominant layers, separated by CO3 groups parallel to {0001}. The main take-home message is to show that not all structure determinations of minerals/compounds can be solved routinely. Some crystals, even large ones displaying excellent diffraction quality, can be twinned in complex ways, thus making their study a crystallographic challenge.

Crystal structure determination of non-stoichiometric Ca4−xRuO6−x (x = 1.17) from X-ray powder diffraction data

2016 ◽  
Vol 31 (1) ◽  
pp. 59-62
Author(s):  
Martin Etter ◽  
Maximilian J. Krautloher ◽  
Nakheon Sung ◽  
Joel Bertinshaw ◽  
Bumjoon Kim ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Powder Diffraction ◽  
Flux Growth ◽  
Powder Diffraction Data ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Growth Method ◽  
Calcium Ruthenate

A new non-stoichiometric calcium ruthenate [Ca4−xRuO6−x with x = 1.17(1)] was synthesized by the flux growth method and characterized by the X-ray powder diffraction. The crystal structure is isostructural to the K4CdCl6 type with space group R$\bar 3$c. Unit-cell parameters are a = 9.2881(1), c = 11.1634(2) Å, V = 834.03(3) Å3, and Z = 6.

The determination of crystal structure of chromium(II) phosphite dihydrate, CrHPO3 2 H2O

1987 ◽  
Vol 52 (7) ◽  
pp. 1742-1747 ◽  
Author(s):  
Jiří Brynda ◽  
Bohumil Kratochvíl ◽  
Ivana Císařová
Keyword(s):  
Crystal Structure ◽  
Heavy Atom ◽  
Cross Linking ◽  
Unit Cell Parameters ◽  
Orthorhombic Space Group ◽  
Interatomic Distances ◽  
Reliability Factor ◽  
Cell Parameters ◽  
Heavy Atom Method

The crystal structure of CrHPO3.2 H2O has been solved by the heavy atom method. The compound crystallizes in the orthorhombic space group P212121 with the unit cell parameters a = 679·25(8), b = 915·61(8), c = 752·2(1) pm, Z = 4. The structure was refined to the final reliability factor R = 0·043 for 1 040 observed reflexions (I > 1·96σ(I)). The structure consists of chains formed by CrO6 octahedra connected each other in vertices. The chains are interconnected by phosphite tetrahedra HPO3. Hydrogen bridges of water-phosphite tetrahedron and water-water types form space cross-linking of the whole structure. Bond distances Cr-O in the tetragonally distorted octahedron range from 201·2 to 304·9 pm. The interatomic distances P-O in phosphite tetrahedron are between 152·1 and 152·7 pm. The degree of the distorsion DISQ of HPO3 tetrahedron and CrO6 octahedron is discussed on the basis of known structures of phosphites and chromium(II) compounds.

Synthesis, vibrational spectra and single-crystal structure determination of lithium tricyanomethanide Li[C(CN)3]

2018 ◽  
Vol 73 (3-4) ◽  
pp. 225-229
Author(s):  
Olaf Reckeweg ◽  
Maurice Conrad ◽  
Armin Schulz ◽  
Francis J. DiSalvo ◽  
Thomas Schleid
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Vibrational Spectra ◽  
Structure Determination ◽  
Metathesis Reaction ◽  
Unit Cell Parameters ◽  
Orthorhombic Space Group ◽  
Cell Parameters ◽  
Related Compounds

AbstractThe long-elusive structure of lithium tricyanomethanide Li[C(CN)3] has been determined on the basis of material synthesized via a metathesis reaction of Ag[C(CN)3] with LiCl in water driven by AgCl precipitation and subsequently recrystallization from methanol. Li[C(CN)3] crystallizes in the non-centrosymmetric orthorhombic space groupIma2 with the unit-cell parametersa=751.06(4),b=1059.75(6) andc=563.27(3) pm adopting a unique structure with planar [C(CN)3]−anions exhibiting nearly ideal trigonal planarD3hsymmetry. The Li+cations are coordinated by five independent tricyanomethanide anions forming a distorted square pyramid with Li–N distances between 202 and 249 pm. The vibrational frequencies were also determined and along with other properties of Li[C(CN)3] compared with those of related compounds.

Tavagnascoite, Bi4O4(SO4)(OH)2, a new oxyhydroxy bismuth sulfate related to klebelsbergite

2016 ◽  
Vol 80 (4) ◽  
pp. 647-657 ◽  
Author(s):  
Luca Bindi ◽  
Cristian Biagioni ◽  
Bruno Martini ◽  
Adrio Salvetti ◽  
Giovanni Dalla Fontana ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
New Mineral ◽  
Chemical Formula ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
Rounding Errors ◽  
X Ray ◽  
Cell Parameters ◽  
Ore District

AbstractThe new mineral tavagnascoite, Bi4O4(SO4)(OH)2, was discovered in the Pb-Bi-Zn-As-Fe-Cu ore district of Tavagnasco, Turin, Piedmont, Italy. It occurs as blocky, colourless crystals, up to 40 μm in size, with a silky lustre. In the specimen studied, tavagnascoite is associated with other uncharacterized secondary Bi-minerals originating from the alteration of a bismuthinite ± Bi-sulfosalt assemblage. Electron microprobe analyses gave (average of three spot analyses, wt.%) Bi2O385.32, Sb2O30.58, PbO 2.18, SO38.46, H2Ocalc1.77, sum 98.31. On the basis of 10 O apfu, the chemical formula is (Bi3.74Pb0.10Sb0.04)∑ = 3.88O3.68(SO4)1.08(OH)2, with rounding errors. Main calculated diffraction lines are [din Å (relative intensity)hkl] 6.39 (29) 012, 4.95 (19) 111,4.019(32)121,3.604(28)014 and 3.213(100)123. Unit-cell parameters area= 5.831(1),b= 11.925(2),c= 15.123(1) Å,V= 1051.6(3) Å3, Z = 4, space groupPca21. The crystal structure was solved and refined from single-crystal X-ray diffraction data toR1= 0.037 on the basis of 1269 observed reflections. It consists of Bi–O polyhedra and SO4tetrahedra. Bismuth polyhedra are connected each to other to form Bi–O sheets parallel to (001). Successive sheets are linked together by SO4groups and hydrogen bonds. Tavagnascoite is the Bi-analogue of klebelsbergite, Sb4O4(SO4)(OH)2, and it is the fifth natural known bismuth sulfate without additional cations. The mineral and its name have been approved by the IMA CNMNC (2014-099).

scholarly journals Mineralogie antimonového výskytu Mikulovický vrch u Kadaně (Česká republika)

2020 ◽  
Vol 28 (1) ◽  
pp. 48-57
Author(s):  
Jiří Sejkora ◽  
Petr Pauliš ◽  
Roman Gramblička ◽  
Ondřej Pour
Keyword(s):  
Raman Spectroscopy ◽  
Czech Republic ◽  
Empirical Formula ◽  
Unit Cell ◽  
Monoclinic Space Group ◽  
Unit Cell Parameters ◽  
Cell Parameters ◽  
Ideal Composition ◽  
The Ideal

Two rare sulfosalt minerals, fülöppite and plagionite, have been determined in samples from a small abandoned Sb occurrence Mikulovický vrch near Kadaň, northern Bohemia, Czech Republic. The more abundant fülöppite forms grey aggregates (up to 5 mm in size) with metallic lustre in quartz gangue and rare crystals up to 1.5 mm across in association with stibnite, plagionite, sphalerite, pyrite and arsenopyrite. Fülöppite is monoclinic, space group C2/c with refined unit-cell parameters: a 13.443(2), b 11.737(2), c 16.953(2) Å, β 94.69(1)° and V 2665.9(5) Å3. Its empirical formula (mean of 93 point analyses) is (Pb2.80Sn0.01Hg0.01)Σ2.82Sb8.18S14.99. Two types of plagionite were found as irregular aggregates up to 200 μm in size in quartz gangue, ussualy in association with fülöppite. The first rarer one is close to the ideal composition with empirical formula (mean of 10 point analyses) (Pb4.90Hg0.01)Σ4.91Sb8.07S17.02; the second is distinctly Pb-poor with the calculated N homologue number in the range of 1.37 - 1.74 and empirical formula (mean of 62 point analyses) (Pb4.31Sn0.02Hg0.01)Σ4.34Sb8.53S17.13. Determination of fülöppite and Pb-poor plagionite were also confirmed by Raman spectroscopy. Gypsum, valentinite, native sulphur and jarosite were detected as products of weathering of primary mineralization.

A Crystallographic Study of Bis[S-benzyl-5-bromo-2-oxoindolin-3-ylidenemethanehydrazonthioate] Disulfide Solvated with Dimethylsulfoxide

2012 ◽  
Vol 9 (2) ◽  
pp. 87
Author(s):  
Mohd Abdul Fatah Abdul Manan ◽  
M. Ibrahim M. Tahir ◽  
Karen A. Crouse ◽  
Fiona N.-F. How ◽  
David J. Watkin
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Solvent Molecule ◽  
Site Occupancy ◽  
Unit Cell Parameters ◽  
Intermolecular Hydrogen Bonds ◽  
Triclinic Space Group ◽  
Cell Parameters ◽  
Crystallographic Study ◽  
Thiol Form

The crystal structure of the title compound has been determined. The compound crystallized in the triclinic space group P -1, Z = 2, V = 1839 .42( 18) A3 and unit cell parameters a= 11. 0460( 6) A, b = 13 .3180(7) A, c=13. 7321 (8) A, a = 80.659(3 )0, b = 69 .800(3 )0 and g = 77 .007 (2)0 with one disordered dimethylsulfoxide solvent molecule with the sulfur and oxygen atoms are distributed over two sites; S101/S102 [site occupancy factors: 0.6035/0.3965] and 0130/0131 [site occupancy factor 0.3965/0.6035]. The C22-S2 l and C 19-S20 bond distances of 1. 779(7) A and 1. 788(8) A indicate that both of the molecules are connected by the disulfide bond [S20-S21 2.055(2) A] in its thiol form. The crystal structure reveals that both of the 5-bromoisatin moieties are trans with respect to the [S21-S20 and CI 9-Nl 8] and [S20-S21 and C22-N23] bonds whereas the benzyl group from the dithiocarbazate are in the cis configuration with respect to [S21-S20 and C19-S44] and [S20-S21 and C22-S36] bonds. The crystal structure is further stabilized by intermolecular hydrogen bonds of N9-H35···O16 formed between the two molecules and N28-H281 ···O130, N28-H281 ···O131 and C4 l-H4 l l ···O 131 with the solvent molecule.

X-ray powder diffraction data of LaNi0.5Ti0.45Co0.05O3, LaNi0.45Co0.05Ti0.5O3, and LaNi0.5Ti0.5O3 perovskites

2021 ◽  
pp. 1-6
Author(s):  
Mariana M. V. M. Souza ◽  
Alex Maza ◽  
Pablo V. Tuza
Keyword(s):  
Crystal Structure ◽  
Rietveld Method ◽  
Pechini Method ◽  
Powder Diffraction Data ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Modified Pechini Method ◽  
Scanning Electron

In the present work, LaNi0.5Ti0.45Co0.05O3, LaNi0.45Co0.05Ti0.5O3, and LaNi0.5Ti0.5O3 perovskites were synthesized by the modified Pechini method. These materials were characterized using X-ray fluorescence, scanning electron microscopy, and powder X-ray diffraction coupled to the Rietveld method. The crystal structure of these materials is orthorhombic, with space group Pbnm (No 62). The unit-cell parameters are a = 5.535(5) Å, b = 5.527(3) Å, c = 7.819(7) Å, V = 239.2(3) Å3, for the LaNi0.5Ti0.45Co0.05O3, a = 5.538(6) Å, b = 5.528(4) Å, c = 7.825(10) Å, V = 239.5(4) Å3, for the LaNi0.45Co0.05Ti0.5O3, and a = 5.540(2) Å, b = 5.5334(15) Å, c = 7.834(3) Å, V = 240.2(1) Å3, for the LaNi0.5Ti0.5O3.

Two lithium tricyanomethanide compounds: syntheses and single-crystal structure determination of LiK[C(CN)3]2 and Li[C(CN)3]·½ (H3C)2CO

2015 ◽  
Vol 70 (3) ◽  
pp. 191-196 ◽  
Author(s):  
Olaf Reckeweg ◽  
Francis J. DiSalvo
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Single Crystals ◽  
Structure Determination ◽  
Monoclinic Space Group ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
Cell Parameters ◽  
New Compounds

AbstractThe new compounds LiK[C(CN)3]2 and Li[C(CN)3]·½ (H3C)2CO were synthesized and their crystal structures were determined. Li[C(CN)3]·½ (H3C)2CO crystallizes in the orthorhombic space group Ima2 (no. 46) with the cell parameters a=794.97(14), b=1165.1(2) and c=1485.4(3) pm, while LiK[C(CN)3]2 adopts the monoclinic space group P21/c (no. 14) with the cell parameters a=1265.7(2), b=1068.0(2) and c=778.36(12) pm and the angle β=95.775(7)°. Single crystals of K[C(CN)3] were also acquired, and the crystal structure was refined more precisely than before corroborating earlier results.

Sign in / Sign up

Export Citation Format

Share Document