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.

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.

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.

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 %.

scholarly journals Synthese und Kristallstruktur eines Alkali-Erdalkali-Kupfer-Halogeno-Oxovanadats: KBaCuV2O7Cl / Synthesis and Crystal Structure of an Alkaline Alkaline-Earth Halide Oxide of Copper and Vanadium: KBaCuV2O7Cl

1994 ◽  
Vol 49 (3) ◽  
pp. 355-359 ◽  
Author(s):  
F.-D. Martin ◽  
H. Müller-Buschbaum
Keyword(s):  
Crystal Structure ◽  
Single Crystals ◽  
Alkaline Earth ◽  
Copper Ion ◽  
Tetragonal Symmetry ◽  
Synthesis And Crystal Structure ◽  
Space Group ◽  
X Ray ◽  
Symmetry Space ◽  
Symmetry Space Group

Abstract Single crystals of KBaCuV2O7Cl have been prepared by a flux technique and investigated by X-ray analysis. The compound crystallizes with tetragonal symmetry, space group C24v-P4 bm, a = 8.8581, c = 5.4711 Å, Z = 2. The crystal structure shows Cu2+ within a one sided strongly distorted CuO4Cl2 octahedron. The copper ion is shifted towards the nearer Cl- neighbour to form a CuO4Cl square pyramid. Two VO4 tetrahedra are connected to give stretched V2O7 double tetrahedra, and linked in planes via the oxygen corners of the CuO4Cl pyramids. The crystal structure and the structure of the complex BaO8Cl2 polyhedron are discussed.

Schmidite and wildenauerite, two new schoonerite-group minerals from the Hagendorf-Süd pegmatite, Oberpfalz, Bavaria

2018 ◽  
Vol 83 (02) ◽  
pp. 181-190
Author(s):  
Ian E. Grey ◽  
Erich Keck ◽  
Anthony R. Kampf ◽  
John D. Cashion ◽  
Colin M. MacRae ◽  
...  
Keyword(s):  
Thermal Analysis ◽  
Tetrahedral Site ◽  
Orthorhombic Symmetry ◽  
Charge Balance ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Symmetry Space ◽  
Symmetry Space Group

AbstractSchmidite, Zn(Fe3+0.5Mn2+0.5)2ZnFe3+(PO4)3(OH)3(H2O)8 and wildenauerite, Zn(Fe3+0.5Mn2+0.5)2Mn2+Fe3+(PO4)3(OH)3(H2O)8 are two new oxidised schoonerite-group minerals from the Hagendorf-Süd pegmatite, Hagendorf, Oberpfalz, Bavaria, Germany. Schmidite occurs as radiating sprays of orange–brown to copper-red laths on and near to altered phosphophyllite in a corroded triphylite nodule, whereas wildenauerite forms dense compacts of red laths, terminating Zn-bearing rockbridgeite. The minerals are biaxial (+) with α = 1.642(2), β = 1.680(1), γ = 1.735(2) and 2Vmeas = 81.4(8)° for schmidite, and with α = 1.659(3), β = 1.687(3), γ = 1.742(3) and 2Vmeas = 73(1)° for wildenauerite. Electron microprobe analyses, with H2O from thermal analysis and FeO/Fe2O3 from Mössbauer spectroscopy, gave FeO 0.4, MgO 0.3, Fe2O3 23.5, MnO 9.0, ZnO 15.5, P2O5 27.6, H2O 23.3, total 99.6 wt.% for schmidite, and FeO 0.7, MgO 0.3, Fe2O3 25.2, MnO 10.7, ZnO 11.5, P2O5 27.2, H2O 24.5, total 100.1 wt.% for wildenauerite. The empirical formulae, scaled to 3 P and with OH– adjusted for charge balance are Zn1.47Mn2+0.98Mg0.05Fe2+0.04Fe3+2.27(PO4)3(OH)2.89(H2O)8.54 for schmidite and Zn1.11Mn2+1.18Mg0.05Fe2+0.08Fe3+2.47(PO4)3(OH)3.25(H2O)9.03 for wildenauerite. The two minerals have orthorhombic symmetry, space group Pmab and Z = 4. The unit-cell parameters from refinement of powder X-ray diffraction data are a = 11.059(1), b = 25.452(1) and c = 6.427(1) Å for schmidite, and a = 11.082(1), b = 25.498(2) and c = 6.436(1) Å for wildenauerite. The crystal structures of schmidite and wildenauerite differ from that of schoonerite in having minor partitioning of Zn from the [5]Zn site to an adjacent vacant tetrahedral site [4]Zn, separated by ~1.0 Å from [5]Zn. The two minerals are distinguished by the cation occupancies in the octahedral M1 to M3 sites. Schmidite has M1 = M2 = (Fe3+0.5Mn2+0.5) and M3 = Zn and wildenauerite has M1 = M2 = (Fe3+0.5Mn2+0.5) and M3 = Mn2+.

Synthese und Röntgen-Strukturuntersuchung von Rb4Cd(VO)(V2O7)2Cl und Tl4Cd(VO)(V2O7)2Cl / Synthesis and X-Ray Structure Analysis of Rb4Cd(VO)(V2O7)2Cl und Tl4Cd(VO)(V2O7)2Cl

1997 ◽  
Vol 52 (4) ◽  
pp. 453-456 ◽  
Author(s):  
B. Mertens ◽  
Hk. Müller-Buschbaum
Keyword(s):  
Single Crystals ◽  
Structure Analysis ◽  
Tetragonal Symmetry ◽  
Space Group ◽  
X Ray ◽  
Vanadyl Group ◽  
Type V ◽  
Symmetry Space ◽  
Symmetry Space Group

Abstract Single crystals of (I) Rb4Cd(VO)(V2O7)2Cl und Tl4Cd(VO)(V2O7)2Cl have been prepared by flux techniques. The compounds were examined by X-ray analysis. They crystallize with tetragonal symmetry, space group C14-P4 with (I): a=9.142(1); c=5.525(1), (II): a=9.150(1), c=5.405(1) A, Z = 4. Both compound belong to the K4CuV5O15Cl-Type. V (l) forms V2O7 double tetrahedra, connected by square V(2)O5 pyramids and CdO4Cl2 octahedra. The short V(2)-O distance indicates a vanadyl group.

Geschlossene 1∞[(PtDy4O16)4]-Polyedertunnel in Ba13Dy8Zn4Pt4O37 Closed 1∞ [(PtDy4O16)4] Polyhedra Tunnels in Ba13Dy8Zn4Pt4O37

1997 ◽  
Vol 52 (5) ◽  
pp. 553-556 ◽  
Author(s):  
O. Sfreddo ◽  
Hk. Müller-Buschbaum
Keyword(s):  
Crystal Structure ◽  
Single Crystals ◽  
Tetragonal Symmetry ◽  
Space Group ◽  
X Ray ◽  
Coordination Numbers ◽  
Symmetry Space ◽  
Symmetry Space Group ◽  
Trigonal Prisms

Abstract Single crystals of Ba13Dy8Zn4Pt4O37 have been prepared by reaction of mixtures of BaCO3, ZnO and DyO3 at temperatures up to 1225 °C using platinum crucibles. X-ray investigations led to a new crystal structure with tetragonal symmetry, space group C4h5-I4/m, a = 18.659(7), c = 5.734(2) Å, Z = 2. The structure is characterized by PtO6 and BaO6 octahedra as well as by tetragonal ZnO5 pyramids and single capped trigonal prisms of oxygen around dysprosium. The remaining barium positions show coordination numbers of nine and ten. The crystal structure has large ∞1[(PtDy4O)6)4] polyhedra tunnels. Considering the ∞1[Ln4O16]20- polyhedra groups some parts of the structure show similarities to BaZnLn2O5, Ba5Zn4Ln8O21 and Ba2Ln2ZnPtO8.

Synthese und röntgenographische Charakterisierung von zwei neuen Verbindungen des Ludwigit-Strukturtyps: Co5Sn(BO3)2O4 und Co5Mn(BO3 )2O4/Synthesis and X -Ray Characterization of Two New Compounds with Ludwigite-Structure: Co5Sn(BO3)2O4 and Co5Mn(BO3)2O4

1996 ◽  
Vol 51 (3) ◽  
pp. 305-308 ◽  
Author(s):  
Anne Utzolino ◽  
Karsten Bluhm
Keyword(s):  
Orthorhombic Symmetry ◽  
X Ray Diffraction ◽  
X Ray ◽  
Oxygen Coordination ◽  
New Compounds ◽  
Octahedral Oxygen ◽  
Group D ◽  
Symmetry Space ◽  
Symmetry Space Group

Abstract The compounds Co5Sn(BO3)2O4 (I) and Co5Mn(BO3)2O4 (II) were prepared by using a B2O3 flux technique. Single crystals were investigated by X-ray diffraction and showed orthorhombic symmetry, space group D2h9-Pbam (No. 55), I a = 944.4; b = 1233.8; c = 310.5 pm; Z = 2 and II a = 925.07; b = 1241.67; c = 305.24 pm; Z = 2. Both compounds are isotypic to the mineral Ludwigite. All metal point positions show an octahedral oxygen coordination. Co2+ and M4+ (M = Sn or Mn) occupy one point position statistically. Both structures contain isolated, trigonal planar BO3 units and oxygen atoms that are not coordinated to boron.

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.

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