scholarly journals Structural properties of the alluaudite-type materials Ag2–xNaxMn3(VO4)3 (x=0.62 and 1.85)

2019 ◽  
Vol 74 (9) ◽  
pp. 677-684
Author(s):  
Hamdi Ben Yahia ◽  
Masahiro Shikano
Keyword(s):  
Solid Solution ◽  
Single Crystal ◽  
X Ray Diffraction ◽  
Monoclinic Symmetry ◽  
Reaction Route ◽  
New Members ◽  
X Ray ◽  
Crystal Structural ◽  
Symmetry Space ◽  
Symmetry Space Group

AbstractThe new members of the Ag2−xNaxMn3(VO4)3 (0 ≤ x ≤ 2) solid solution were synthesized by a solid-state reaction route. The crystal structures of Ag1.38Na0.62Mn3(VO4)3 (x = 0.62) and Ag0.15Na1.85Mn3(VO4)3 (x = 1.85) were solved using single crystal X-ray diffraction. These phases crystallize with a monoclinic symmetry (space group C2/c), and their structures are new members of the well-known alluaudite family. In both compounds, the Ag+/Na+, Mn2+/Mn3+ and V5+ cations are eight-, six-, and four-coordinated to oxygen atoms, respectively. All the atoms are perfectly ordered except for the Ag and Na atoms which are statistically disordered over a 4b and a 4e atomic position. This single-crystal structural study confirms the existence of a full solid solution Ag2−xNaxMn3(VO4)3 (0 ≤ x ≤ 1.85).

Crystal chemistry of the compound Sr2Bi2CuO6

1990 ◽  
Vol 5 (1) ◽  
pp. 46-52 ◽  
Author(s):  
R. S. Roth ◽  
C. J. Rawn ◽  
L. A. Bendersky
Keyword(s):  
Electron Diffraction ◽  
Single Crystal ◽  
Diffraction Pattern ◽  
Crystal Chemistry ◽  
Superconducting Phase ◽  
X Ray Diffraction ◽  
Monoclinic Symmetry ◽  
X Ray ◽  
Symmetry Space ◽  
Symmetry Space Group

The compound Sr2Bi2CuO6 should nominally be the phase with n = 1 of the high Tc superconducting series Sr2Bi2CanO4+2n. However, the superconducting phase with n = 1 (with no CaO) occurs only with a gross deficiency in SrO content. Instead, at the composition Sr2Bi2CuO6, a different phase is formed with an x-ray diffraction pattern considerably different from that expected for the n −1 member of the series. This phase has been found, by a combination of electron diffraction and single crystal and powder x-ray diffraction, to have a commensurate lattice with monoclinic symmetry, space group C2/m or Cm, a = 24.473 (2), b = 5.4223 (5), c = 21.959 (2)A, and β = 105.40 (1)°. The actual composition of this phase may be deficient in CuO by as much as 1.0 mole %.

Crystal Structure of the New Phosphate AgMnPO4

2009 ◽  
Vol 64 (7) ◽  
pp. 875-878 ◽  
Author(s):  
Hamdi Ben Yahia ◽  
Etienne Gaudin ◽  
Jacques Darriet
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Diffraction Data ◽  
X Ray Diffraction ◽  
Reaction Route ◽  
X Ray ◽  
Solid State Reaction Route ◽  
Symmetry Space ◽  
Symmetry Space Group ◽  
Silver Atoms

The new compound AgMnPO4 has been synthesized by a solid-state reaction route. Its crystal structure was determined from single-crystal X-ray diffraction data. AgMnPO4 crystallizes with triclinic symmetry, space group P1̄, a = 9.6710(6), b = 5.695(2), c = 6.629(3) Å , α = 102.55(3), β = 105.85(2), γ = 80.70(2)◦, and Z = 4. Its structure is built up from MnO6, MnO5 and PO4 polyhedra forming tunnels filled with silver atoms.

The low-temperature form of calcium gold stannide, CaAuSn

2014 ◽  
Vol 70 (8) ◽  
pp. 773-775 ◽  
Author(s):  
Qisheng Lin ◽  
John D. Corbett
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Single Crystal ◽  
Diffraction Analysis ◽  
Orthorhombic Symmetry ◽  
X Ray Diffraction ◽  
X Ray ◽  
Symmetry Space ◽  
High Temperature Polymorph ◽  
Symmetry Space Group

The EuAuGe-type CaAuSn phase has been synthesized and single-crystal X-ray diffraction analysis reveals that it has an orthorhombic symmetry (space groupImm2), witha= 4.5261 (7) Å,b= 7.1356 (11) Å andc= 7.8147 (11) Å. The structure features puckered layers that are connected by homoatomic Au—Au and Sn—Sn interlayer bonds. This structure is one of the two parent structures of its high-temperature polymorph (ca873 K), which is an intergrowth structure of the EuAuGe- and SrMgSi-type structures in a 2:3 ratio.

Zur Synthese und Kristallstruktur von Kupferzinkpyroboratoxid Cu2Zn(B2O5)O / Synthesis and Crystal Structure of Copper Zinc Pyroborate Oxide Cu2Zn(B2O5)O

1995 ◽  
Vol 50 (12) ◽  
pp. 1854-1858 ◽  
Author(s):  
Silke Busche ◽  
Karsten Bluhm
Keyword(s):  
Crystal Structure ◽  
X Ray Diffraction ◽  
Monoclinic Symmetry ◽  
Synthesis And Crystal Structure ◽  
X Ray ◽  
Square Planar ◽  
Significant Difference ◽  
Copper Zinc ◽  
Symmetry Space ◽  
Symmetry Space Group

The compound Cu2Zn(B2O5)O was prepared by using a B2O3 flux technique, and single crystals were investigated by X-ray diffraction (monoclinic symmetry, space group C52h-P21/c ). The structure is isotypic to Cu2Co(B2O5)O with lattice parameters a = 327.38(2), b = 1479.4(3), c = 915.39(13), β = 95.794(11)°, Z = 4, but with the significant difference that zinc is pentacoordinated by oxygen. Copper exhibits a nearly square planar or a square pyramidal coordination, respectively. The structure contains isolated B2O5 units and oxygen which is not coordinated to boron.

scholarly journals Photoconductivity of the Single Crystals Pb4Ga4GeS12 and Pb4Ga4GeSe12

Proceedings ◽  
2020 ◽  
Vol 62 (1) ◽  
pp. 4
Author(s):  
Hadj Bellagra ◽  
Oksana Nyhmatullina ◽  
Yuri Kogut ◽  
Halyna Myronchuk ◽  
Lyudmyla Piskach
Keyword(s):  
Ternary Systems ◽  
Semiconductor Materials ◽  
Tetragonal Symmetry ◽  
Bandgap Energy ◽  
Experimental Measurements ◽  
X Ray Diffraction ◽  
X Ray ◽  
Vertical Bridgman ◽  
Symmetry Space ◽  
Symmetry Space Group

Quaternary semiconductor materials of the Pb4Ga4GeS(Se)12 composition have attracted the attention of researchers due to their possible use as active elements of optoelectronics and nonlinear optics. The Pb4Ga4GeS(Se)12 phases belong to the solid solution ranges of the Pb3Ga2GeS(Se)8 compounds which form in the quasi-ternary systems PbS(Se)−Ga2S(Se)3−GeS(Se)2 at the cross of the PbGa2S(Se)4−Pb2GeS(Se)4 and PbS(Se)−PbGa2GeS(Se)6 sections. The quaternary sulfide melts congruently at 943 K. The crystallization of the Pb4Ga4GeSe12 phase is associated with the ternary peritectic process Lp + PbSe ↔ PbGa2S4 + Pb3Ga2GeSe8 at 868 K. For the single crystal studies, Pb4Ga4GeS(Se)12 were pre-synthesized by co-melting high-purity elements. The X-ray diffraction results confirm that these compounds possess non-centrosymmetric crystal structure (tetragonal symmetry, space group P–421c). The crystals were grown by the vertical Bridgman method in a two-zone furnace. The starting composition was stoichiometric for Pb4Ga4GeS12, and the solution-melt method was used for the selenide Pb4Ga4GeSe12. The obtained value of the bandgap energy for the Pb4Ga4GeS12 and Pb4Ga4GeSe12 crystals is 1.86 and 2.28 eV, respectively. Experimental measurements of the spectral distribution of photoconductivity for the Pb4Ga4GeS12 and Pb4Ga4GeSe12 crystals exhibit the presence of two spectral maxima. The first lies in the region of 570 (2.17 eV) and 680 nm (1.82 eV), respectively, and matches the optical bandgap estimates well. The locations of the admixture maxima at about 1030 (1.20 eV) and 1340 nm (0.92 eV), respectively, agree satisfactorily with the calculated energy positions of the defects vs. and VSe.

Synthese und Röntgenstrukturanalyse von KCuGd2Mo4O16 und KCuTb2Mo4O16/Synthesis and X-Ray Analysis of KCuGd2Mo4O16 and KCuTb2Mo4O16

1995 ◽  
Vol 50 (12) ◽  
pp. 1794-1798 ◽  
Author(s):  
Hk. Müller-Buschbaum ◽  
St. Gallinat
Keyword(s):  
Lattice Energy ◽  
Rare Earth Ions ◽  
Monoclinic Symmetry ◽  
X Ray ◽  
Coulomb Term ◽  
Relationship Of ◽  
The Relationship ◽  
Symmetry Space ◽  
Oxidation State Of Copper ◽  
Symmetry Space Group

Single crystals of the so far unknown compounds KCuGd2Mo4O16 (I) and KCuTb2Mo4O16 (II) have been prepared by flux technique. The compounds crystallize with monoclinic symmetry. space group C62h-C2 /c with (I): a = 5.278(2), b = 12.666(5), c = 19.604(14) Å; β = 92.76(6)°; (II): a = 5.259(13), b = 12.616(3), c = 19.556(9) Å, β = 92.93(4)°, Z = 4. Molybdenum exhibits tetrahedral coordination. The surroundings of copper can be described by distorted tetrahedra, capped by two more distant oxygen atoms, and the rare earth ions show a square antiprism. Potassium is inside an irregular polyhedron. The relationship of the structures of (I) and (II) is discussed with respect to the KLnMo2O8 type compounds. Coulomb term calculations of the lattice energy indicate an oxidation state of copper higher than CuI.

Crystal chemistry of lamprophyllite-group minerals from the Murun alkaline complex (Russia) and pegmatites of Rocky Boy and Gordon Butte (USA): single crystal X-ray diffraction and Raman spectroscopy study

2021 ◽  
Vol 77 (2) ◽  
Author(s):  
Sergey M. Aksenov ◽  
Anastasia D. Ryanskaya ◽  
Yuliya V. Shchapova ◽  
Nikita V. Chukanov ◽  
Nikolay V. Vladykin ◽  
...  
Keyword(s):  
Solid Solution ◽  
Single Crystal ◽  
Raman Spectra ◽  
Crystal Chemistry ◽  
Solid Solution Series ◽  
X Ray Diffraction ◽  
Alkaline Complex ◽  
Oh Groups ◽  
X Ray ◽  
Solution Series

Specific features of the crystal chemistry of lamprophyllite-group minerals (LGMs) are discussed using the available literature data and the results of the single-crystal X-ray diffraction and a Raman spectroscopic studies of several samples taken from the Murun alkaline complex (Russia), and Rocky Boy and Gordon Butte pegmatites (USA) presented here. The studied samples are unique in their chemical features and the distribution of cations over structural sites. In particular, the sample from the Gordon Butte pegmatite is a member of the barytolamprophyllite–emmerichite solid solution series, whereas the samples from the Murun alkaline complex and from the Rocky Boy pegmatite are intermediate members of the solid solution series formed by lamprophyllite and a hypothetical Sr analogue of emmerichite. The predominance of O2− over OH− and F− at the X site is a specific feature of sample Cha-192 from the Murun alkaline complex. New data on the Raman spectra of LGMs obtained in this work show that the wavenumbers of the O—H stretching vibrations depend on the occupancies of the M2 and M3 sites coordinating with (OH)− groups. Cations other than Na+ and Ti4+ (mainly, Mg and Fe3+) can play a significant role in the coordination of the X site occupied by (OH)−. Data on polarized Raman spectra of an oriented sample indicate that the OH groups having different local coordinations have similar orientations with respect to the crystal. The calculated measures of similarity (Δ) for lamprophyllite and ericssonite are identical (0.157 and 0.077 for the 2M- and 2O-polytypes, respectively), which indicates that these minerals are crystal-chemically isotypic and probably should be considered within the same mineral group by analogy to the other mineralogical groups which combine isotypic minerals.

Synthese und Struktureines Strontium-Vanadyl-Phosphats: Sr2(VO)(PO4)2 / Synthesis and Structure of a Strontium Vanadyl Phosphate: Sr2(VO)(PO4)2

1996 ◽  
Vol 51 (7) ◽  
pp. 929-933 ◽  
Author(s):  
C. Wadewitz ◽  
Hk. Müller-Buschbaum
Keyword(s):  
Solid State ◽  
Solid State Reactions ◽  
Vanadyl Phosphate ◽  
Monoclinic Symmetry ◽  
X Ray ◽  
Vanadyl Group ◽  
Dark Green ◽  
Symmetry Space ◽  
Oxygen Distance ◽  
Symmetry Space Group

Dark green single crystals of Sr2(VO)P2O8 have been prepared by solid state reactions in closed quartz tubes. X-ray investigations led to monoclinic symmetry, space group C2h6-I2/a, a = 6.744(4), b = 15.866(4), c = 7.032(2) Å, β = 115.41(2), Z = 4. Sr2(VO)P2O8 is isotypic to Sr2(VO)V2O8 and shows V4+ in split positions. The split positions are in non-centric octahedral coordination forming a short vanadium to oxygen distance typical for the vanadyl group. The crystal chemistry of the monovanadyl orthophate Sr2(VO)P2O8 is discussed considering related divanadyl phosphates.

scholarly journals Low-Temperature Ordering in the Cluster Compound (Bi8)Tl[AlCl4]3

Inorganics ◽  
2019 ◽  
Vol 7 (4) ◽  
pp. 45 ◽  
Author(s):  
Maximilian Knies ◽  
Martin Kaiser ◽  
Mai Lê Anh ◽  
Anastasia Efimova ◽  
Thomas Doert ◽  
...  
Keyword(s):  
Cluster Compound ◽  
Structure Model ◽  
X Ray Diffraction ◽  
Hexagonal Symmetry ◽  
Threefold Axis ◽  
Space Group ◽  
X Ray ◽  
A Chain ◽  
Symmetry Space ◽  
Symmetry Space Group

The reaction of Bi, BiCl3, and TlCl in the ionic liquid [BMIm]Cl·4AlCl3 (BMIm = 1-n-butyl-3-methylimidazolium) at 180 °C yielded air-sensitive black crystals of (Bi8)Tl[AlCl4]3. X-ray diffraction on single crystals at room temperature revealed a structure containing [ Tl ( AlCl 4 ) 3 ] ∞ 1 2 − strands separated by isolated Bi82+ square antiprisms. The thallium(I) ion is coordinated by twelve Cl− ions of six [AlCl4]− groups, resulting in a chain of face-sharing [TlCl12]11− icosahedra. The Bi82+ polycation is disordered, simulating a threefold axis through its center and overall hexagonal symmetry (space group P63/m). Slowly cooling the crystals to 170 K resulted in increased order in the Bi8 cluster orientations. An ordered structure model in a supercell with a’ = 2a, b’ = 2b, c’ = 3c and the space group P65 was refined. The structure resembles a hexagonal perovskite, with complex groups in place of simple ions.

Synthesis and crystallographic studies of two new 1,3,5-triazines

2020 ◽  
Vol 76 (4) ◽  
pp. 322-327
Author(s):  
Emmanuel Blas Patricio-Rangel ◽  
Margarita Tlahuextl ◽  
Hugo Tlahuext ◽  
Antonio Rafael Tapia-Benavides
Keyword(s):  
Noncovalent Interactions ◽  
Synthesis And Characterization ◽  
Water Molecules ◽  
X Ray Diffraction ◽  
X Ray ◽  
Positional Disorder ◽  
Hydrated Salt ◽  
Symmetry Space ◽  
Symmetry Space Group

The synthesis and characterization of two new 1,3,5-triazines containing 2-(aminomethyl)-1H-benzimidazole hydrochloride as a substituent are reported, namely, 2-{[(4,6-dichloro-1,3,5-triazin-2-yl)amino]methyl}-1H-benzimidazol-3-ium chloride, C11H9Cl2N6 +·Cl− (1), and bis(2,2′-{[(6-chloro-1,3,5-triazine-2,4-diyl)bis(azanediyl)]bis(methylene)}bis(1H-benzimidazol-3-ium)) tetrachloride heptahydrate, 2C19H18ClN9 2+·4Cl−·7H2O (2). Both salts were characterized using single-crystal X-ray diffraction analysis and IR spectroscopy. Moreover, the NMR (1H and 13C) spectra of 1 were obtained. Salts 1 and 2 have triclinic symmetry (space group P-1) and their supramolecular structures are stabilized by hydrogen bonding and offset π–π interactions. In hydrated salt 2, the noncovalent interactions yield pseudo-nanotubes filled with chloride anions and water molecules, which were modelled in the refinement with substitutional and positional disorder.

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