Crystal structure of the high-temperature form of the trisulfide Cs2S3 and the (3+1)D modulated structure of the telluride K37Te28

2019 ◽  
Vol 74 (1) ◽  
pp. 33-47 ◽  
Author(s):  
Pirmin Stüble ◽  
Angela Berroth ◽  
Fritz Wortelkamp ◽  
Caroline Röhr
Keyword(s):  
High Temperature ◽  
Elemental Sulfur ◽  
Structure Type ◽  
Monoclinic Space Group ◽  
Compound K ◽  
Modulated Structure ◽  
Space Group ◽  
Different Types ◽  
High Temperature Form ◽  
High Temperature Polymorph

AbstractThe high-temperature polymorph of the trisulfide Cs2S3, which has been synthesized from Cs2S2 and elemental sulfur, crystallizes in a new structure type (monoclinic, space group P21/c, a=999.97(4), b=1029.30(5), c=2642.07(12) pm, β=90.083(2)°, Z=16, R1=0.0324). The structure contains four crystallographically independent angled ${\rm{S}}_3^{2 - }$ trisulfide ions with S–S distances of 205.7–208.3 pm. The distorted b.c.c. packing of the anions and their insertion in the five-membered rings of 3.53+3.5.3.5. (1:1) Cs nets are similarly found in the r.t. form (Cmc21, K2S3-type structure) and the two polymorphs differ mainly in the orientation of the S3 groups. The second title compound, K37Te28, was synthesized from stoichiometric melts of the elements. It forms a complex (3+1)D modulated tetragonal structure (space group I41/amd (00σ3)s0s0, q=(0, 0, 0.5143), a=1923.22(2), c=2626.66(4) pm, Z=4, R1all=0.0837). According to K37Te28=K37[Te(1X)]8[Te(2X)2]6[Te(3X)8] the structure contains three different types of Te anions: The two crystallographically different isolated telluride anions [Te(1X)]2− are coordinated by 9/10 K+ cations. Three [Te(2X)2]2− dumbbells (dTe-Te=277.9/286.4 pm) are arranged to ‘hexamers’. The Te(31) and Te(32) atoms are located in columns of face-sharing K square antiprisms. Their z position modulation, which is accompanied by a smaller shift of the surrounding K+ cations, results in the decomposition of the [Te(3X)8]2 chain in a sequence |:Te3–Te2–Te2–Te3–Te2–Te2–Te2:| of dumbbells Te22− (dTe–Te=304 pm) and hypervalent linear trimers Te34− (dTe–Te=325 pm).

Crystal data for NH(CH3)3GeCl3

1982 ◽  
Vol 15 (2) ◽  
pp. 247-248 ◽  
Author(s):  
A. Möller ◽  
J. Felsche
Keyword(s):  
High Temperature ◽  
Phase Change ◽  
Perovskite Structure ◽  
Room Temperature ◽  
Structure Type ◽  
Crystal Data ◽  
Space Group ◽  
Cell Parameters ◽  
Orthorhombic Modification ◽  
High Temperature Form

NH(CH3)3GeCl3, C3H10N+.Ge2+.3Cl−, crystallizes at room temperature in an orthorhombic modification with a = 9.537(2), b = 8.235(2), c = 12.138(2) Å, Z = 4, space group Cmc21. These cell parameters correspond to a derivative of the cubic perovskite structure type, with a≃b≃\sqrt{2} a cubic and c≃ 2a cubic. Unlike other chlorogermanates(II) there is not a phase change to an ionically conducting cubic high-temperature form.

Ein neues kationenreiches Oxogallat Zur Kenntnis von K2Li3GaO4/A New Cation Rich Oxogallate About K2Li3GaO4

1983 ◽  
Vol 38 (2) ◽  
pp. 130-138 ◽  
Keyword(s):  
Graph Theory ◽  
Single Crystals ◽  
Structure Type ◽  
Monoclinic Space Group ◽  
Compound K ◽  
Coordination Polyhedra ◽  
Space Group ◽  
Binary Oxides ◽  
Coordination Polyhedrons

Abstract The new compound K2Li3GaO4 was prepared from binary oxides (powder) and from LiGaO2/KO0.48 (colourless transparent single crystals) in a closed Ag cylinder at 600 °C. It crystallizes in the monoclinic space group P21/c with the constants a = 553.6(2) 6 = 880.4(3) c = 1093.1(4) pm β = 111.52(3)°. Z = 4, drö = 3.017 and dpyk = 2.97 g·cm-3 . [4-circle diffractometer data, 1333 I0 (hkl), Mo-Ka, R = 4.95 and Rw = 5.04%, anisotropic refinement.] The new structure type is complicated. The characteristical features are shown using Schlegel projections of the coordination polyhedrons. Extended Schlegel Diagrams, a novel application of graph theory, are used. They describe bijective how the coordination polyhedra are three-dimensionally combined.

Two reversible enantiotropic phase transitions in a pentacoordinate silicon complex with anO,N,O′-tridentate valinate ligand

2015 ◽  
Vol 71 (6) ◽  
pp. 511-516 ◽  
Author(s):  
Anke Schwarzer ◽  
Sabine Fels ◽  
Uwe Böhme
Keyword(s):  
Phase Transitions ◽  
High Temperature ◽  
Low Temperature ◽  
Monoclinic Space Group ◽  
Isopropyl Group ◽  
Orthorhombic Space Group ◽  
Chiral Compound ◽  
Space Group ◽  
Temperature Form ◽  
High Temperature Form

Dimethyl[N-(4-oxidopent-3-en-2-ylidene)valinato-κ3O,N,O′]silicon(IV), C12H21NO3Si, (II), crystallizes in the orthorhombic space groupP212121. The chiral compound undergoes two sharp enantiotropic phase transitions upon cooling. The first transformation occurs at 163 K to yield a unit cell with one axis having double length. This intermediate-temperature form has the monoclinic space groupP21. The second transition takes place at 142 K and converts the single crystal into the low-temperature form in the orthorhombic space groupP212121. This transition proceeds under tripling of theaaxis of the high-temperature form. Both phase transitions are fully reversible and correspond to order–disorder transitions of the isopropyl group of the valine unit in the ligand backbone. The phase transitions presented here raise questions, since they do not fit into the rules of group–subgroup relationships.

New mixed-valent alkali chain sulfido ferrates A1+x[FeS2] (A = K, Rb, Cs; x = 0.333–0.787)

2020 ◽  
Vol 235 (8-9) ◽  
pp. 275-290
Author(s):  
Michael Schwarz ◽  
Pirmin Stüble ◽  
Katharina Köhler ◽  
Caroline Röhr
Keyword(s):  
Alkali Metal ◽  
General Structure ◽  
Variable Number ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Modulated Structure ◽  
Space Group ◽  
X Ray ◽  
Local Coordination ◽  
Natural Pyrite

AbstractFour new mixed-valent chain alkali metal (A) sulfido ferrates of the general structure family ${A}_{1+x}\left[{\text{Fe}}_{x}^{\text{II}}{\text{Fe}}_{1-x}^{\text{III}}{\text{S}}_{2}\right]$ were synthesized in the form of tiny green-metallic needles from nearly stoichiometric melts reacting elemental potassium with natural pyrite (A = K) or previously prepared Rb2S/Cs2S2 with elemental iron and sulfur (A = Rb/Cs). The crystal structures of the compounds were determined by means of single crystal X-ray diffraction: In the (3+1)D modulated structure of K7.15[FeS2]4 (space group Ccce(00σ3)0s0, a = 1363.87(5), b = 2487.23(13), c = 583.47(3) pm, q = 0,0,0.444, R1 = 0.055/0.148, x = 0.787), a position modulation of the two crystallographically different undulated ${}_{\infty }{}^{1}\left[{\text{FeS}}_{4/2}\right]$ tetrahedra chains and the surrounding K cations is associated with an occupation modulation of one of the three potassium sites. In the case of the new monoclinic rubidium ferrate Rb4[FeS2]3 (x = $\frac{1}{3}$; space group P21/c, a = 1640.49(12), b = 1191.94(9), c = 743.33(6) pm, β = 94.759(4)°, Z = 4, R1 = 0.1184) the undulation of the tetrahedra chain is commensurate, the repetition unit consists of six tetrahedra. In the second new Rb ferrate, Rb7[FeS2]5 (x = 0.4; monoclinic, space group C2/c, K7[FeS2]5-type; a = 2833.9(2), b = 1197.36(9), c = 744.63(6) pm, β = 103.233(4)°, Z = 4, R1 = 0.1474) and its isotypic mixed Rb/Cs-analog Rb3.6Cs3.4[FeS2]5 (a = 2843.57(5), b = 1226.47(2), c = 759.890(10) pm, β = 103.7170(9)°, R1 = 0.0376) the chain buckling leads to a further increased repetition unit of 10 tetrahedra. For all mixed-valent ferrates, the Fe–S bond lengths continuously increase with the amount (x) of Fe(II). The buckling of the chains is controlled through the local coordination of the S atoms by the variable number of A cations of different sizes.

Gemischte Alkalimetall-Oxidosulfidomolybdate A2[MoOxS4– x] (x = 1, 2, 3; A = K, Rb, Cs, NH4). Synthesen, Kristallstrukturen und Eigenschaften / Mixed Alkali Oxidosulfidomolybdates A2[MoOxS4−x] (x = 1, 2, 3; A = K, Rb, Cs, NH4).Synthesis, Crystal Structure and Properties

2012 ◽  
Vol 67 (2) ◽  
pp. 127-22
Author(s):  
Anna J. Lehner ◽  
Korina Kraut ◽  
Caroline Röhr
Keyword(s):  
Bathochromic Shift ◽  
Structure Type ◽  
Structure Theory ◽  
Monoclinic Space Group ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
Coordination Numbers ◽  
Preparation Conditions ◽  
Vis Spectroscopy ◽  
Type Orthorhombic

Mixed sulfido/oxidomolybdate anions [MoOxS4−x]2− (x = 1, 2, 3) have been prepared by passing H2S gas through a solution of oxidomolybdates. The alkali salts of K+, Rb+, Cs+, and NH+4 precipitate as crystalline salts from these solutions depending on the pH, the polarity of the solvent, the educt concentrations and the temperature. Their structures have been determined by means of X-ray single-crystal diffraction data. All trisulfidomolybdates A2[MoOS3] (A = NH4/K/Rb/Cs) are isotypic with the tetrasulfido salts, exhibiting the β -K2[SO4] type (orthorhombic, space group Pnma, Z = 4; for A = Rb: a = 940.62(4), b = 713.32(4), c = 1164.56(5) pm, R1 = 0.0281). In contrast, the disulfidomolybdates exhibit a rich crystal chemistry, forming three different structure types depending on the preparation conditions and the size of the A cation: All four cations form salts crystallizing with the (NH4)2[WO2S2] structure type (monoclinic, space group C2/c, Z = 4, for A = Rb: a = 1144.32(11), b = 732.60(4), c = 978.99(10) pm, β = 120.324(7)°, R1 = 0.0274). For the three alkali metal cations a second polymorph with a new structure type (monoclinic, space group P21/c, Z = 4) is observed in addition (for A = Rb: a = 674.83(2), b = 852.98(3), c = 1383.10(9) pm, β = 115.19(1)°, R1 = 0.0216). The cesium salt also crystallizes with a third modification of another new structure type (orthorhombic, space group Pbcn, Z = 4, a = 915.30(6), b = 777.27(7), c = 1120.02(7) pm, R1 = 0.0350). Only for K, an anhydrous monosulfidomolybdate could be obtained (K2[MoO4] structure type, monoclinic, space group C2/m, Z = 4, a = 1288.7(3), b = 615.7(2), c = 762.2(1) pm, β = 109.59(1)°, R1 = 0.0736). The intramolecular chemical bonding in the molybdate anions is discussed and compared with the respective vanadates. Hereby aspects like bond lengths, bond strengths and force constants derived from Raman spectroscopy, are taken into account. Especially for the polymorphic disulfido salts, in-depth analyses of the local coordination numbers and the packing of the ions are presented. The gradual bathochromic shift of the crystal color with increasing S content and increasing size of the counter cations A and molar volumes (for the polymorphic forms), respectively, is in accordance with the increase of the experimental (UV/Vis spectroscopy) and calculated (FP-LAPW band structure theory) band gaps.

Cation ordering in the double tungstate LiFe(WO4)2

2012 ◽  
Vol 68 (2) ◽  
pp. i7-i8 ◽  
Author(s):  
Marjorie Albino ◽  
Stanislav Pechev ◽  
Philippe Veber ◽  
Matias Velazquez ◽  
Michael Josse
Keyword(s):  
High Temperature ◽  
Cation Ordering ◽  
Monoclinic Space Group ◽  
High Temperature Solution ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
Double Tungstate ◽  
Growth Method ◽  
Temperature Solution ◽  
Expected Values

Single crystals of lithium iron tungstate, LiFe(WO4)2, were obtained using a high-temperature solution growth method. The analysis was conducted using the monoclinic space groupC2/c, with β = 90.597 (2)°, givingR1 = 0.0177. The Li and Fe atoms lie on twofold axes. The structure can also be refined using the orthorhombic space groupCmcm, giving slightly higher residuals. The experimental value of β and the residuals mitigate in favour of the monoclinic description of the structure. Calculated bond-valence sums for the present results are closer to expected values than those obtained using the results of a previously reported analysis of this structure.

Investigation of mesitylene-solvated group 13 mixed-metal halides: syntheses and crystal structures of bis(1,3,5-trimethylbenzene)gallium(I) tetrachlorido- and tetrabromidoaluminate(III) and (1,3,5-trimethylbenzene)gallium(I) tetraiodidoaluminate(III). Variation of the gallium-π-arene bond strength

2019 ◽  
Vol 74 (10) ◽  
pp. 773-782
Author(s):  
Luca Küppers ◽  
Walter Frank
Keyword(s):  
Structure Type ◽  
Monoclinic Space Group ◽  
Metal Halides ◽  
Group 13 ◽  
Space Group ◽  
X Ray ◽  
Mixed Metal ◽  
Main Group Metal ◽  
Arene Complex ◽  
Polymeric Chains

AbstractBis(1,3,5-trimethylbenzene)gallium(I) tetra­chloridoaluminate(III), [(1,3,5-(CH3)3C6H3)2Ga][AlCl4] (1), bis(1,3,5-trimethylbenzene)gallium(I) tetrabromido­aluminate(III), [(1,3,5-(CH3)3C6H3)2Ga][AlBr4] (2) and (1,3,5-trimethylbenzene)gallium(I) tetraiodidoaluminate(III), [1,3,5-(CH3)3C6H3Ga][AlI4] (3) were synthesized from the corresponding subvalent GaI/AlIII mixed metal halides and characterized via C,H analysis, Raman spectroscopy, X-ray powder diffraction and X-ray single crystal diffraction. Compound 1 crystallizes in the noncentrosymmetric monoclinic space group Cc isotypic to [(1,3,5-(CH3)3C6H3)2Ga][GaCl4]. For 2 and 3 the monoclinic space group P21/n is found, however, they are neither isotypic nor homotypic. While 2 is isotypic to [(1,3,5-(CH3)3C6H3)2In][InBr4], 3 establishes a new structure type. In the solids of all three title compounds coordination polymeric chains are found, in 1 and 2 built up from bis(arene)-coordinated, in 3 from mono(arene)-coordinated Ga+ ions and the corresponding AlX4− anions in a 1κCl:2κCl′ (1), 1κCl,Cl′:2κCl″ (2) or 1κCl,Cl′:2κCl″:3κCl‴ (3) bridging mode. Taking into account the weaker coordinating character of the AlCl4− as compared to the AlBr4− anion, in line with expectations the number of gallium halogen contacts is increased and the strength of the π-arene bonding is reduced in the bromide 2 as compared to the chloride 1. Finally, with the even more strongly coordinating AlI4− anion the arene coordination is limited to one molecule. Considering mesitylene complexes of gallium, the formation of a mono(arene) complex is unprecedented and even considering group 13 elements in general, the formation of a mono(mesitylene) complex like 3 is unusual. Furthermore, compound 3 is the first structurally characterized arene solvate of a main group metal tetraiodidometallate.

Irreversible single-crystal to polycrystal and reversible single-crystal to single-crystal phase transformations in cyanurates

2001 ◽  
Vol 57 (6) ◽  
pp. 791-799 ◽  
Author(s):  
Menahem Kaftory ◽  
Mark Botoshansky ◽  
Moshe Kapon ◽  
Vitaly Shteiman
Keyword(s):  
Phase Transformation ◽  
High Temperature ◽  
Low Temperature ◽  
Single Crystal ◽  
High Temperature Phase ◽  
Monoclinic Space Group ◽  
Temperature Phase ◽  
Space Group ◽  
Reversible Phase ◽  
Low Temperature Phase

4,6-Dimethoxy-3-methyldihydrotriazine-2-one (1) undergoes a single-crystal to single-crystal reversible phase transformation at 319 K. The low-temperature phase crystallizes in monoclinic space group P21/n with two crystallographically independent molecules in the asymmetric unit. The high-temperature phase is obtained by heating a single crystal of the low-temperature phase. This phase is orthorhombic, space group Pnma, with the molecules occupying a crystallographic mirror plane. The enthalpy of the transformation is 1.34 kJ mol−1. The small energy difference between the two phases and the minimal atomic movement facilitate the single-crystal to single-crystal reversible phase transformation with no destruction of the crystal lattice. On further heating, the high-temperature phase undergoes methyl rearrangement in the solid state. 2,4,6-Trimethoxy-1,3,5-triazine (3), on the other hand, undergoes an irreversible phase transformation from single-crystal to polycrystalline material at 340 K with an enthalpy of 3.9 kJ mol−1; upon further heating it melts and methyl rearrangement takes place.

scholarly journals On the high temperature phase transition in Ba(Zr0.20Ti0.80)O3 ceramic

2017 ◽  
Vol 07 (04) ◽  
pp. 1750025 ◽  
Author(s):  
K. P. Chandra ◽  
A. R. Kulkarni ◽  
K. Prasad
Keyword(s):  
Phase Transition ◽  
High Temperature ◽  
Lattice Structure ◽  
High Temperature Phase ◽  
Monoclinic Space Group ◽  
Temperature Phase ◽  
Potential Candidate ◽  
Space Group ◽  
Structure Changes ◽  
Temperature Phase Transition

Temperature dependent X-ray diffraction (XRD) and dielectric properties of perovskite Ba(Zr[Formula: see text]Ti[Formula: see text]O3 ceramic prepared using a standard solid-state reaction process is presented. Along with phase transitions at low temperature, a new phase transition at high temperature (873[Formula: see text]C at 20[Formula: see text]Hz), diffusive in character has been found where the lattice structure changes from monoclinic (space group: [Formula: see text] to hexagonal (space group: [Formula: see text]). This result places present ceramic in the list of potential candidate for intended high temperature applications. The AC conductivity data followed hopping type charge conduction and supports jump relaxation model. The experimental value of [Formula: see text][Formula: see text]pC/N was found. The dependence of polarization and strain on electric field at room temperature suggested that lead-free Ba(Zr[Formula: see text]Ti[Formula: see text]O3 is a promising material for electrostrictive applications.

CaAgxZn1– x: Zwischen CrB- und FeB-Strukturtyp – Eine Studie zu elektronischen Einflüssen auf die Stapelung von Zick-Zack-Ketten in polaren Erdalkalimetall-Monometalliden / CaAgxZn1−x: Between CrB and FeB Structure Type – A Study on Electronic Factors Influencing the Stacking of Zig-zag Chains in Polar Alkaline Earth Monometallides

2009 ◽  
Vol 64 (10) ◽  
pp. 1127-1142 ◽  
Author(s):  
Wiebke Harms ◽  
Viktoria Mihajlov ◽  
Marco Wendorff ◽  
Caroline Röhr
Keyword(s):  
Alkaline Earth ◽  
Valence Electron ◽  
Computational Study ◽  
Structure Type ◽  
Binary Compound ◽  
Monoclinic Space Group ◽  
Stacking Sequence ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
Type Orthorhombic

Depending on both electronic (valence electron numbers) and geometric (atom size ratios) characteristics of the contributing elements, the 1 : 1 compounds AIIM of the heavier alkaline earth elements A and electron-rich transition metals M form the well known CrB or FeB structure types. Both structure types exhibit M zig-zag chains, which are stacked in different orientations. In systematic studies of the pseudo-binary section CaAgxZn1−x four new ternary phases with different stacking variants between the CrB (cubic stacking, c) and the FeB (hexagonal stacking, h2) structure type have been prepared and characterized on the basis of single crystal X-ray data. Starting from CaAg (CrB type, orthorhombic, space group Cmcm, a = 405.22(7), b = 1144.7(2), c = 464.43(11) pm, Z = 4, R1 = 0.0197), up to 24% of Ag (CaAg0.76Zn0.24: a = 408.6(2), b = 1144.3(5), c = 460.7(2) pm, R1 = 0.0208) can be substituted by zinc without a change in the structure type. Close to the 1 : 1 ratio of Ag and Zn, the HT-TbNi structure type with the stacking sequence (hc2)2, i. e. 33% hexagonality (CaAg0.52Zn0.48: orthorhombic, space group Pnma, a = 2345.47(6), b = 454.370(10), c = 609.950(10) pm, Z = 12, R1 = 0.0298) is formed, followed by the SrAg type with 50% hexagonality (CaAg0.48Zn0.52: orthorhombic, space group Pnma, a = 1571.0(2), b = 451.50(7), c = 609.80(9) pm, Z = 8, R1 = 0.0733). The amount of hexagonal stacking is further increased with increasing Zn content in CaAg0.33Zn0.67 (Gd0.7Y0.3 structure type, h2c stacking, 67% hexagonality, monoclinic, space group P21/m, a = 610.39(9), b = 448.53(5), c = 1195.7(2) pm, β = 96.829(14)◦, Z = 3, R1 = 0.0221). Finally, a pure hexagonal stacking sequence, i. e. the FeB structure type (orthorhombic, space group Pnma, Z = 4) is observed from CaAg0.14Zn0.86 (a = 804.57(2), b = 443.050(10), c = 611.350(10) pm, R1 = 0.0131) to CaAg0.06Zn0.94 (a = 806.1(3), b = 441.0(2), c = 610.4(3) pm, R1 = 0.0255). Intriguingly, the series ends with the binary compound CaZn, which again crystallizes with the CrB structure type exhibiting cubic stacking of the zig-zag chains only (0% hexagonality). In an accompanying computational study, the chemical bonding in the series Ca(Ge/Ga/Zn/Ag) of isotypic binary metallides with variable valence electron numbers has been analyzed using FP-LAPW band structure methods. The electronic structures of the two border stacking variants are compared using the crystal data of CaZn (CrB type) and CaAg0.06Zn0.94 (FeB type). Geometrical and electronic criteria are used to compare and discuss the stability ranges of the different stacking variants inbetween the CrB and the FeB structure type found in polar intermetallic 1 : 1 phases.

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