Synthesis and crystal structure of C2/c Ca(Co,Mg)Si2O6 pyroxenes: effect of the cation substitution on cell volume

2017 ◽  
Vol 81 (5) ◽  
pp. 1129-1139 ◽  
Author(s):  
C. Gori ◽  
M. Tribaudino ◽  
L. Mantovani ◽  
G. D. Gatta ◽  
D. Delmonte ◽  
...  

AbstractA series of clinopyroxenes along the CaMgSi2O6–CaCoSi2O6 join was synthesized by quenching from melts at 1500°C and subsequent annealing at 1250°C (at 0.0001 GPa). This protocol proved to be the most effective to obtain homogenous, impurity-free and stoichiometric pyroxenes. Electron microprobe analyses in energy dispersive mode were conducted and single-crystal X-ray diffraction data were collected on Ca (CoxMg1-x)Si2O6 pyroxenes with x = 0.2, 0.4, 0.5, 0.6. Effects of cation substitution at the M1 site are described. The experimental findings of this study allow us to extend the comparative analysis of the structural features of pyroxenes with divalent cations at the M1 and M2 sites.

2019 ◽  
Vol 74 (4) ◽  
pp. 357-363
Author(s):  
Daniela Vitzthum ◽  
Hubert Huppertz

AbstractThe mixed cation triel borate Ga4In4B15O33(OH)3 was synthesized in a Walker-type multianvil apparatus at high-pressure/high-temperature conditions of 12.5 GPa and 1300°C. Although the product could not be reproduced in further experiments, its crystal structure could be reliably determined via single-crystal X-ray diffraction data. Ga4In4B15O33(OH)3 crystallizes in the tetragonal space group I41/a (origin choice 2) with the lattice parameters a = 11.382(2), c = 15.244(2) Å, and V = 1974.9(4) Å3. The structure of the quaternary triel borate consists of a complex network of BO4 tetrahedra, edge-sharing InO6 octahedra in dinuclear units, and very dense edge-sharing GaO6 octahedra in tetranuclear units.


2013 ◽  
Vol 28 (1) ◽  
pp. 13-17 ◽  
Author(s):  
F. Laufek ◽  
A. Vymazalová ◽  
D.A. Chareev ◽  
A.V. Kristavchuk ◽  
J. Drahokoupil ◽  
...  

The (Ag,Pd)22Se6 phase was synthesized from individual elements by silica glass tube technique and structurally characterized from powder X-ray diffraction data. The (Ag,Pd)22Se6 phase crystallizes in Fm$\overline3$m symmetry, unit-cell parameters: a = 12.3169(2) Å, V = 1862.55(5) Å3, Z = 4, and Dc = 10.01 g/cm3. The crystal structure of the (Ag,Pd)22Se6 phase represents a stuffed 3a.3a.3a superstructure of the Pd structure (fcc), where only 4 from 108 available octahedral holes are occupied. Its crystal structure is related to the Cr23C6 structure type.


1985 ◽  
Vol 40 (3) ◽  
pp. 443-446 ◽  
Author(s):  
Udo Demant ◽  
Elke Conradi ◽  
Ulrich Müller ◽  
Kurt Dehnicke

[HC(NH2)2]3FeCl6 was obtained together with other products from the reaction of S4N4 with HCl in H2CCl2 in the presence of FeCl3. Its crystal structure was determined from X-ray diffraction data (473 independent observed reflexions, R = 0.047). Lattice constants: a = 961.6, c = 876.4 pm; tetragonal, space group P42/m, Z = 2. Of the two crystallographically independent formamidinium ions HC(NH2)2⊕, one exhibits positional disorder; the other one has C-N bond lengths of 128 pm. The FeCl63⊖ ions have symmetry C2h, but the deviation from Oh is small.


2010 ◽  
Vol 65 (10) ◽  
pp. 1206-1212 ◽  
Author(s):  
Almut Haberer ◽  
Reinhard Kaindl ◽  
Hubert Huppertz

The praseodymium orthoborate λ -PrBO3 was synthesized from Pr6O11, B2O3, and PrF3 under high-pressure / high-temperature conditions of 3 GPa and 800 °C in a Walker-type multianvil apparatus. The crystal structure was determined on the basis of single-crystal X-ray diffraction data, collected at room temperature. The title compound crystallizes in the orthorhombic aragonite-type structure, space group Pnma, with the lattice parameters a = 577.1(2), b = 506.7(2), c = 813.3(2) pm, and V = 0.2378(2) nm3, with R1 = 0.0400 and wR2 = 0.0495 (all data). Within the trigonal-planar BO3 groups, the average B-O distance is 137.2 pm. The praseodymium atoms are ninefold coordinated by oxygen atoms.


2018 ◽  
Vol 74 (3) ◽  
pp. 295-299 ◽  
Author(s):  
Evgeniya A. Ptashkina ◽  
Elizaveta G. Kabanova ◽  
Anna I. Tursina ◽  
Alexandr V. Yatsenko ◽  
Victor N. Kuznetsov

A new Cu3Au-type ternary phase (τ phase) is found in the AuPd-rich part of the Au–In–Pd system. It has a broad homogeneity range based on extensive (Pd,Au) and (In,Au) replacement, with the composition varying between Au17.7In25.3Pd57.0and Au50.8In16.2Pd33.0. The occupancies of the crystallographic positions were studied by single-crystal X-ray diffraction for three samples of different composition. The sites withm\overline{3}msymmetry are occupied by atoms with a smaller scattering power than the atoms located on 4/mmmsites. Two extreme structure models were refined. Within the first, the occupation type changes from (Au,In,Pd)3(Pd,In) to (Au,Pd)3(In,Pd,Au) with an increase in the Au gross content. For the second model, the occupation type (Au,In,Pd)3(Pd,Au) remains essentially unchanged for all Au concentrations. Although the diffraction data do not allow the choice of one of these models, the latter model, where Au substitutes In on 4/mmmsites, seems to be preferable, since it agrees with the fact that the homogeneity range of the τ phase is inclined to the Au corner and provides the same occupation type for all the studied samples of different compositions.


1985 ◽  
Vol 40 (10) ◽  
pp. 1320-1326 ◽  
Author(s):  
Joachim Müller ◽  
Ulrich Müller ◽  
Almuth Loss ◽  
Jörg Lorberth ◽  
Harald Donath ◽  
...  

Reaction of Me2SbBr or Et2SbBr with AgN3 in ether affords Me2SbN3 and Et:SbN3. respectively. Me2SbN3 can also be obtained from Me2SbNMe2 and HN3 in ether. Me2BiN3 from Me2BiN(SiMe3)3 and HN3 in ether. Me2SbN3 and Et2SbN3 dissolve as monomers in benzene; 1H, 13C, iaN and 15N NMR spectra of the solutions are reported. IR and Raman spectra of solid Me2SbN3 and Et2SbN, as well as the mass spectrum of Me2SbN3 are assigned. The crystal structures of Me2SbN3 and Me2BiN3 were determined by X-ray diffraction data collected at -67 °C (888 and 439 reflexions, R = 0.024 and 0.076. respectively). Both compounds are isotypic, space group Pnma. Z = 4. Crystal data: Me2SbN3, a = 843.6. b = 919.3, c = 744.1 pm: Me2BiN3, a - 870.8. b = 911.3, c = 738.4 pm. In the crystals, the metal atoms are linked via the aN atoms of the azido groups to form endless zig-zag chains. Whereas the Bi -N distances are equal. Sb-N bonds alternate with two different lengths (232 and 243 pm). Including the lone pair of electrons, the metal coordination can be described as distorted trigonal bipyramidal, with nitrogen atoms occupying the apical positions. With new X-ray diffraction data collected at -100 °C, the crystal structure of Me3PbN3 was refined (1692 reflexions, R = 0.036). Crystal data: a = 656.3, c = 1377 pm. space group P3221, Z = 3. It consists of endless metal-nitrogen chains of helical symmetry. the Pb atoms having trigonal bipyramidal coordination.


2010 ◽  
Vol 65 (5) ◽  
pp. 643-645 ◽  
Author(s):  
Volodymyr Smetana ◽  
Arndt Simon

A new binary compound in the system Ba-In has been synthesized and structurally characterized. According to singlecrystal X-ray diffraction data Ba9In4 crystallizes with tetragonal symmetry (I4/m, a = 13.948(2), c = 5.888(1) Å, V = 1145.5(3) Å3, Z = 2, R1 = 0.037, wR2 = 0.071). The very moisture-sensitive compound could be obtained as single phase by reaction of metallic barium and indium at 350 °C.


2020 ◽  
Vol 75 (8) ◽  
pp. 765-768
Author(s):  
Bohdana Belan ◽  
Dorota Kowalska ◽  
Mariya Dzevenko ◽  
Mykola Manyako ◽  
Roman Gladyshevskii

AbstractThe crystal structure of the phase Ce5AgxGe4−x (x = 0.1−1.08) has been determined using single-crystal X-ray diffraction data for Ce5Ag0.1Ge3.9. This phase is isotypic with Sm5Ge4: space group Pnma (No. 62), Pearson code oP36, Z = 4, a = 7.9632(2), b = 15.2693(5), c = 8.0803(2) Å; R1 = 0.0261, wR2 = 0.0460, 1428 F2 values and 48 variables. The two crystallographic positions 8d and 4c show Ge/Ag mixing, leading to a slight increase in the lattice parameters as compared to those of the pure binary compound Ce5Ge4.


2020 ◽  
Vol 235 (8-9) ◽  
pp. 311-317
Author(s):  
Stephan G. Jantz ◽  
Florian Pielnhofer ◽  
Henning A. Höppe

Abstract${\text{Pb}}_{5}{\text{O}}_{2}\left[{\text{WO}}_{6}\right]$ was discovered as a frequently observed side phase during our investigation on lead tungstates. Its crystal structure was solved by single-crystal X-ray diffraction ($P{2}_{1}/n$, $a=7.4379\left(2\right)$ Å, $b=12.1115\left(4\right)$ Å, $c=10.6171\left(3\right)$ Å, $\beta =90.6847\left(8\right)$°, $Z=4$, ${R}_{\text{int}}=0.038$, ${R}_{1}=0.020$, $\omega {R}_{2}=0.029$, 4188 data, 128 param.) and is isotypic with ${\text{Pb}}_{5}{\text{O}}_{2}\left[{\text{Te}}_{6}\right]$. ${\text{Pb}}_{5}{\text{O}}_{2}\left[{\text{WO}}_{6}\right]$ comprises a layered structure built up by non-condensed [WO6]${}^{6-}$ octahedra and ${\left[{\text{O}}_{4}{\text{Pb}}_{10}\right]}^{12+}$ oligomers. The compound was characterised by spectroscopic measurements (Infrared (IR), Raman and Ultraviolet–visible (UV/Vis) spectra) as well as quantum chemical and electrostatic calculations (density functional theory (DFT), MAPLE) yielding a band gap of 2.9 eV fitting well with the optical one of 2.8 eV. An estimation of the refractive index based on the Gladstone-Dale relationship yielded $n\approx 2.31$. Furthermore first results of the thermal analysis are presented.


2010 ◽  
Vol 95 (4) ◽  
pp. 655-658 ◽  
Author(s):  
S. Nazzareni ◽  
P. Comodi ◽  
L. Bindi ◽  
L. Dubrovinsky

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