scholarly journals Fedorite from Murun Alkaline Complex (Russia): Spectroscopy and Crystal Chemical Features

Minerals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 702
Author(s):  
Ekaterina V. Kaneva ◽  
Roman Yu. Shendrik ◽  
Tatiana A. Radomskaya ◽  
Ludmila F. Suvorova
Keyword(s):  
Crystal Structure ◽  
Emission Spectra ◽  
Chemical Study ◽  
Double Layers ◽  
Water Molecules ◽  
Crystal Chemical ◽  
Alkaline Complex ◽  
Deformation Parameters ◽  
First Time ◽  
Red Coloration

Fedorite is a rare phyllosilicate, having a crystal structure characterized by SiO4-tetrahedral double layers located between continuous layers formed by edge-sharing (Ca,Na)-octahedra, and containing interlayer K, Na atoms and H2O molecules. A mineralogical-petrographic and detailed crystal-chemical study of fedorite specimens from three districts of the Murun alkaline complex was performed. The sequence of the crystallization of minerals in association with fedorite was established. The studied fedorite samples differ in the content of interlayer potassium and water molecules. A comparative analysis based on polyhedral characteristics and deformation parameters was carried out. For the first time, EPR, optical absorption and emission spectra were obtained for fedorite. The raspberry-red coloration of the mineral specimens could be attributed to the presence of Mn4+ ions.

Crystal structure of magnesium dichloride decahydrate determined by X-ray and neutron diffraction under high pressure

2015 ◽  
Vol 71 (1) ◽  
pp. 74-80 ◽  
Author(s):  
Kazuki Komatsu ◽  
Ayako Shinozaki ◽  
Shinichi Machida ◽  
Takuto Matsubayashi ◽  
Mao Watanabe ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Neutron Diffraction ◽  
Amorphous State ◽  
Water Molecules ◽  
X Ray ◽  
The Difference ◽  
Diffraction Patterns ◽  
Difference Fourier ◽  
First Time

Magnesium dichloride decahydrate (MgCl2·10H2O) and its deuterated counterpart (MgCl2·10D2O) are identified for the first time byin-situpowder synchrotron X-ray and spallation neutron diffraction. These substances are crystallized from a previously unidentified nanocrystalline compound, which originates from an amorphous state at low temperature. A combination of a recently developed autoindexing procedure and the charge-flipping method reveals that the crystal structure of MgCl2·10H2O consists of an ABCABC... sequence of Mg(H2O)6octahedra. The Cl−anions and remaining water molecules unconnected to the Mg2+cations bind the octahedra, similar to other water-rich magnesium dichloride hydrates. The D positions in MgCl2·10D2O, determined by the difference Fourier methods using the neutron powder diffraction patterns at 2.5 GPa, show the features such as bifurcated hydrogen bonds and tetrahedrally coordinated O atoms, which were not found in other forms of magnesium chloride hydrates.

Metavivianite, Fe2+Fe3+2(PO4)2(OH)2·6H2O: new data and formula revision

2012 ◽  
Vol 76 (3) ◽  
pp. 725-741 ◽  
Author(s):  
N. V. Chukanov ◽  
R. Scholz ◽  
S. M. Aksenov ◽  
R. K. Rastsvetaeva ◽  
I. V. Pekov ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Gas Chromatography ◽  
Optical Properties ◽  
Crystal Chemical ◽  
Chemical Formula ◽  
Crystal Chemical Formula ◽  
Homogeneous Sample ◽  
X Ray ◽  
Composition Structure ◽  
First Time

AbstractThe composition, structure, X-ray powder diffraction pattern, optical properties, density, infrared, Raman and Mössbauer spectra, and thermal properties of a homogeneous sample of metavivianite from the Boa Vista pegmatite, near Galiléia, Minas Gerais, Brazil are reported for the first time. Metavivianite is biaxial (+) with α = 1.600(3), β = 1.640(3), γ = 1.685(3) and 2Vmeas= 85(5)°. The measured and calculated densities are Dmeas= 2.56(2) and Dcalc= 2.579 g cm–3. The chemical composition, based on electronmicroprobe analyses, Mössbauer spectroscopy (to determine the Fe2+:Fe3+ratio) and gas chromatography (to determine H2O) is MgO 0.70, MnO 0.92, FeO 17.98, Fe2O326.60, P2O528.62, H2O 26.5; total 101.32 wt.%. The empirical formula is (Fe3+1.64Fe2+1.23Mg0.085Mn0.06)Σ3.015(PO4)1.98(OH)1.72·6.36H2O. Metavivianite is triclinic, P1̄, a = 7.989(1), b = 9.321(2), c = 4.629(1) Å, α = 97.34(1), β = 95.96(1), γ = 108.59(2)°, V = 320.18(11) Å3and Z = 1. The crystal structure was solved using a single-crystal techniques to an agreement index R = 6.0%. The dominant cations in the independent sites are Fe2+and Fe3+, with multiplicities of 1 and 2, respectively. The simplified crystal-chemical formula for metavivianite is Fe2+(Fe3+, Fe2+)2(PO4)2(OH,H2O)2·6H2O; the endmember formula is Fe2+Fe3+2(PO4)2(OH)2·6H2O, which is dimorphous with ferrostrunzite.

The crystal structure of veenite

2017 ◽  
Vol 81 (2) ◽  
pp. 355-368 ◽  
Author(s):  
Dan Topa ◽  
Emil Makovicky
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Type Locality ◽  
Double Layers ◽  
Unit Cell Parameters ◽  
Single Crystal Diffraction ◽  
X Ray ◽  
Cell Parameters ◽  
First Time ◽  
Pb Substitution

AbstractThe crystal structure of veenite is reported for the first time from a sample from the type locality of Madoc (Ontario, Canada). It has been solved and refined by X-ray single-crystal diffraction on the basis of 4973 observed reflections (with Fo > 4σ(Fo)) with a final R1 = 0.0396. Veenite is monoclinic P21, with unit-cell parameters a = 8.429(2), b = 26.069(5), c = 8.962(2) Å, β = 117.447(2)o. The bulk veenite composition is Ag0.15Pb16.029Sb8.836As6.99S39.95 (for Z = 1) corresponding to N = 4.09 (Me8NS8N + 8, theoretical value is 4.0), with the percentage of the Ag-(As,Sb) substituted end-member only equal to 3.51 mol.%, i.e., a nearly pure Pb-Sb-As sulfosalt. The crystal structure is typical for the N = 4 sartorite homologue, with zig-zag walls of trigonal coordination prisms of Pb which separate slabs of diagonally oriented double-layers populated by Sb and As with partial Pb substitution. Orientation of three-membered crankshaft chains formed by strong (As,Sb) – S bonds on the two surfaces of double-layers differs substantially from that in dufrénoysite, which is a pure Pb-As (N = 4) sulfosalt.

Molybdophyllite: crystal chemistry, crystal structure, OD character and modular relationships with britvinite

2012 ◽  
Vol 76 (3) ◽  
pp. 493-516 ◽  
Author(s):  
U. Kolitsch ◽  
S. Merlino ◽  
D. Holtstam
Keyword(s):  
Crystal Structure ◽  
Layered Silicate ◽  
Chemical Study ◽  
Spectroscopic Studies ◽  
Sensu Stricto ◽  
Crystal Chemical ◽  
X Ray Diffraction ◽  
Space Group ◽  
Raman Spectroscopic ◽  
Ir And Raman

AbstractA detailed crystal-chemical study of the complex layered silicate molybdophyllite was conducted using single-crystal X-ray diffraction (XRD) methods, supplemented by powder XRD, infrared (IR) and Raman spectroscopic studies, chemical analyses by energy-dispersive spectrometry (EDS) on a scanning electron microscope (SEM), and electron probe microanalysis (EPMA). The results, based on several samples from both Långban and Harstigen, Filipstad, Sweden, show that the crystal structure of molybdophyllite has an order-disorder (OD) character. The latter is especially evident in specimens from Långban which display a complex diffraction pattern characterized by the simultaneous presence of sharp spots, diffuse reflections and continuous streaks. The sharp reflections define the unit cell of the family structure (a = 3.124, c = 41.832 Å, space group R32). Two main polytypes (maximum degree of order structures) are indicated by the OD approach: a trigonal one and a monoclinic one; the latter polytype is the most common in the samples that were studied and has space group C2, with a = 16.232(6), b = 9.373(2), c = 14.060(3) Å, b = 97.36(4)º and V = 2121.5(10) Å3.The crystal structure determination [R1= 0.096], together with the EPMA, IR and Raman data, reveal that molybdophyllite is built up by a regular alternation of complex layers with a composition {Mg9[Si10O28(OH)8][OPb4]2}6+and simple layers with a composition [(CO3)3·H2O]6–, leading to the ideal crystal-chemical formula Pb8Mg9[Si10O28(OH)8|O2|(CO3)3]·H2O (Z = 2).This contribution is mainly devoted to the results obtained for molybdophyllite sensu stricto, but new data for britvinite [i.e. 'molybdophyllite-18 Å'] are also presented and its modular relationship with molybdophyllite is discussed.

Hydrogen Bonds in the Crystal Structure of Strontium Hydroxide Octahydrate Sr(OH)2 · 8H2O

2007 ◽  
Vol 62 (2) ◽  
pp. 215-219 ◽  
Author(s):  
Hans Reuter ◽  
Shouassi Kamaha ◽  
Otmane Zerzouf
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Water Molecules ◽  
Hydrogen Atoms ◽  
Coordination Polyhedra ◽  
Linear Chains ◽  
Weak Hydrogen Bonds ◽  
Strontium Hydroxide ◽  
First Time ◽  
Additional Hydrogen

Strontium hydroxide octahydrate Sr(OH)2 · 8 H2O crystallizes in the tetragonal space group P4/ncc with cell constants a = 9.017(1) and c = 11.603(1) Å . The crystal structure has been refined from 2656 diffractometer data up to 2ϑ = 60° to an R value of 0.0303. With the new diffraction data it was possible to localize the positions of all hydrogen atoms for the first time and to describe the hydrogen bonding scheme in detail. The Sr2+ ions are square antiprismatically coordinated by eight water molecules. These {Sr(H2O)8}2+ coordination polyhedra are linked with each other via hydrogen bonds in a way that linear columns parallel to the c axis result. The two hydroxyl anions of the asymmetric unit are linked by weak hydrogen bonds and are not coordinated to strontium atoms. Like the strontium atoms, they form linear chains parallel to the c axis. Both, {Sr(H2O)8}2+ columns and OH- chains, are interconnected through two types of additional hydrogen bonds.

Synthesis, IR spectroscopy and crystal structure of [(UO2)2{Be(H2O)2(PO4)2}]·(H2O), the first compound with a trimer beryllophosphate anion

2018 ◽  
Vol 233 (6) ◽  
pp. 391-398 ◽  
Author(s):  
Fabrice Dal Bo ◽  
Sergey M. Aksenov ◽  
Frédéric Hatert ◽  
Peter C. Burns
Keyword(s):  
Crystal Structure ◽  
Ir Spectroscopy ◽  
Water Molecule ◽  
Interlayer Space ◽  
Direct Methods ◽  
Water Molecules ◽  
Unit Cell Parameters ◽  
Hydrothermal Conditions ◽  
Cell Parameters ◽  
First Time

Abstract The first uranyl beryllophosphate, [(UO2)2{Be(H2O)2(PO4)2}]·(H2O), has been synthesized under hydrothermal conditions at 200°C. The monoclinic unit-cell parameters are: a=9.3361(1), b=8.8545(4), c=9.6592(10) Å, β=93.211(1)°, V=797.21(6) Å3, space group P2/n, Z=2. The crystal structure has been solved by direct methods and refined to final R1=4.92% using 1294 I>3σ(I) reflections in the anisotropic approximation. The structure consists of sheets of UrO5 pentagonal bipyramids and PO4 tetrahedra. UrO5 bipyramids are linked by edge-sharing to form infinite chains. Adjacent chains of UrO5 bipyramids are connected by sharing alternating edges of uranyl bipyramids with PO4 tetrahedra. The resulting sheets are based on the well-known uranophane anion-topology. Be atoms are tetrahedrally coordinated by two oxygen atoms of PO4 tetrahedra and two water molecules in the interlayer space. One isolated water molecule also occurs in the interlayer space, where it is held in position by H bonds. The connection between the phosphorus and beryllium tetrahedra leads to formation of an unbranched trimer [BeP2O8(H2O)2]4− observed for the first time in inorganic oxysalts.

(±)-2,2-Dimethyl-5-oxotetrahydrofuran-3-carboxylic acid (terebic acid): a racemic layered structure

2012 ◽  
Vol 68 (8) ◽  
pp. o294-o297
Author(s):  
L. M. Santos ◽  
A. O. Legendre ◽  
P. C. M. Villis ◽  
C. Viegas Jr ◽  
A. C. Doriguetto
Keyword(s):  
Crystal Structure ◽  
Carboxylic Acid ◽  
Hydrogen Bonds ◽  
Layered Structure ◽  
Chemical Compound ◽  
Crystalline Form ◽  
Double Layers ◽  
Industrial Chemical ◽  
First Time

A racemic crystalline form of terebic acid, C7H10O4, which is an important industrial chemical compound, is reported for the first time. The crystal structure is stabilized by O—H...O and C—H...O hydrogen bonds which form racemic double layers parallel to (001).

scholarly journals The crystal structure of sucrose sodium bromide dihydrate

1947 ◽  
Vol 190 (1021) ◽  
pp. 257-272 ◽  
Keyword(s):  
Crystal Structure ◽  
Direct Proof ◽  
The Other ◽  
Sodium Bromide ◽  
Water Molecules ◽  
Hydroxyl Groups ◽  
Pyranose Ring ◽  
Complete Structure ◽  
The Mean ◽  
First Time

The complete crystal structure of sucrose sodium bromide dihydrate has been determined. The crystals are orthorhombic, with space-group P 2 1 2 1 2 1 , and cell-edges a =21.92, b =9.72, c =8.43 A. The bromine positions were obtained from Patterson-Harker syntheses, and the signs of the F ’s of the (0 kl ), ( h 0 l ) and ( hk 0) planes from the change of intensity from the chloride to bromide compounds. Fourier projections parallel to the three axes were used to determine the complete structure. In the structure the pyranose ring of the molecule is of the Sachse trans form. The furanose ring is an unexpectedly compact grouping, and one member of the ring is displaced from the plane of the other four. The configuration of both rings is such as to allow the groups attached to the ring atoms to approach as nearly as possible to the mean plane of each ring. Direct proof that sucrose may be described as α - d -glucopyranosido- β - d -fructofuranoside has been obtained for the first time. The sucrose molecules are held together by bonds from the hydroxyl groups to the Na and Br ions and to the water molecules, the hydroxyl groups each having two external bonds. The method used of reducing the observed intensities to an absolute scale is described, and the proof of the correctness of the structure is given as a set of diagrams of calculated and observed electron density.

The Role of Sorptive Layers in the Formation And Change of the Crystal Structure of Montmorillonite

Clay Minerals ◽  
1970 ◽  
Vol 8 (3) ◽  
pp. 255-266 ◽  
Author(s):  
M. V. Eirish ◽  
L. I. Tret'Yakova
Keyword(s):  
Crystal Structure ◽  
Diffraction Analysis ◽  
Chemical Structure ◽  
Interaction Mechanism ◽  
Sorption Process ◽  
Water Molecules ◽  
Crystal Chemical ◽  
X Ray Diffraction ◽  
X Ray

AbstractThe influence of sorbed cations and hydration on the a and b dimensions of montmorillonite, has been established by the selected area diffraction technique (S.A.D.) and by X-ray diffraction analysis. Concepts on the bonds and interaction mechanism of aluminosilicate layers with sorbed cations and water molecules (which form hydrate-ionic layers) are discussed. These concepts also indicate the basic stages of the sorption process and the formation of the montmorillonite structure. Assuming that aluminosilicate and hydrate-ionic layers represent a single crystal-chemical structure, the change of configuration of the aluminosilicate layers and dimensions of the montmorillonite lattice are explained.

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