BaGe8As14 - a semiconducting sodalite type compound

2021 ◽  
Author(s):  
Dirk Johrendt ◽  
Valentin Weippert ◽  
Thanh Chau ◽  
Kristian Witthaut ◽  
Lucien Eisenburger

The new sodalite type compound BaGe8As14 was synthesized via solid-state reactions and structurally characterized with single crystal X-ray diffraction (space group I-43m). Vertex-sharing GeAs4-tetrahedra form the β-cages with additional Ge/As...

1995 ◽  
Vol 50 (4) ◽  
pp. 699-701 ◽  
Author(s):  
Norbert W. Mitzel ◽  
Jürgen Riede ◽  
Klaus Angermaier ◽  
Hubert Schmidbaur

The solid-state structure of N,N-dibenzylhydroxylamine (1) has been determined by single crystal X-ray diffraction. The compound crystallizes in the monoclinic space group P 21/n with four formula units in the unit cell. N,N-dibenzylhydroxylamine dimerizes to give N2O2H2 sixmembered rings as a result of the formation of two hydrogen bonds O - H ··· N in the solid state.


1994 ◽  
Vol 9 (3) ◽  
pp. 648-657 ◽  
Author(s):  
J.S. Chen ◽  
E. Kolawa ◽  
M-A. Nicolet ◽  
R.P. Ruiz ◽  
L. Baud ◽  
...  

Thermally induced solid-state reactions between a 70 nm Pt film and a single-crystal (001) β-SiC substrate at temperatures from 300 °C to 1000 °C for various time durations are investigated by 2 MeV He backscattering spectrometry, x-ray diffraction, secondary ion mass spectrometry, scanning electron microscopy, and cross-sectional transmission electron microscopy. Backscattering spectrometry shows that Pt reacts with SiC at 500 °C. The product phase identified by x-ray diffraction is Pt3Si. At 600–900 °C, the main reaction product is Pt2Si, but the depth distribution of the Pt atoms changes with annealing temperature. When the sample is annealed at 1000 °C, the surface morphology deteriorates with the formation of some dendrite-like hillocks; both Pt2Si and PtSi are detected by x-ray diffraction. Samples annealed at 500–900 °C have a double-layer structure with a silicide surface layer and a carbon-silicide mixed layer below in contact with the substrate. The SiC—Pt interaction is resolved at an atomic scale with high-resolution electron microscopy. It is found that the grains of the sputtered Pt film first align themselves preferentially along an orientation of {111}Pt//{001}SiC without reaction between Pt and SiC. A thin amorphous interlayer then forms at 400 °C. At 450 °C, a new crystalline phase nucleates discretely at the Pt-interlayer interface and projects into or across the amorphous interlayer toward the SiC, while the undisturbed amorphous interlayer between the newly formed crystallites maintains its thickness. These nuclei grow extensively down into the substrate region at 500 °C, and the rest of the Pt film is converted to Pt3Si. Comparison between the thermal reaction of SiC-Pt and that of Si–Pt is discussed.


2013 ◽  
Vol 69 (12) ◽  
pp. i84-i84 ◽  
Author(s):  
Aicha Mbarek ◽  
Fadhila Edhokkar

The crystal structure of strontium diarsenate has been reinvestigated from single-crystal X-ray diffraction data. In contrast to the previous determinations of this structure [Weilet al.(2009).Solid State Sci.11, 2111–2117; Edhokkaret al.(2012).Mater. Sci. Eng.,28, 012017] and to all isotypicA2B2O7compounds that crystallize in the space groupP41, the current redetermination revealed theP43enantiomorph of Sr2As2O7with a purity of 96.3 (8)%. The crystal structure is made up from two eclipsed As2O7diarsenate groups (symmetry 1) with characteristically longer As—O bridging bonds [1.756 (4)–1.781 (4) Å] than the terminal As—O bonds [1.636 (4)–1.679 (4) Å] and four Sr2+sites with coordination numbers ranging from seven to nine. The building units are arranged in sheets parallel to (001).


2007 ◽  
Vol 62 (1) ◽  
pp. 1-4 ◽  
Author(s):  
Nachiappan Arumugam ◽  
Eva-Maria Peters ◽  
Martin Jansen

A new potassium molybdenum oxide, K6Mo10O33, was synthesized by solid state reaction from the appropriate quantities of pre-dried MoO3 and K2MoO4, fired at around 650 °C for 2 d. The structure has been solved by using single crystal X-ray diffraction. The compound adopts the space group P1, with the lattice constants a = 7.7100(5), b = 11.9659(8), c = 17.1321(12) A° , α = 86.42 (10), β = 77.18(10), γ = 74.14(10)°. The structure is built up of infinite chains of edge-sharing MoO6 octahedra and groups of four MoO6 octahedra forming Mo4O17 units. These sub-units are connected together by common vertices.


2020 ◽  
Vol 75 (11) ◽  
pp. 983-989
Author(s):  
Valentin Weippert ◽  
Arthur Haffner ◽  
Dirk Johrendt

AbstractThe new supertetrahedral compounds MSiAs2, MGaSiAs3 and mC/tI-M4Ga5SiAs9 (M = Sr, Eu) have been synthesized by solid-state reactions at high temperatures. The structures were determined by single crystal or powder X-ray diffraction. MSiAs2 and MGaSiAs3 crystallize in the monoclinic TlGaSe2- and RbCuSnS3-type structures, respectively (space group C2/c). These are topologically hierarchical variants of the tetragonal HgI2-type structure with stacked layers of T2 or T3 supertetrahedra. The T4 compounds M4Ga5SiAs9 are dimorphic and form new structure types in the space groups C2/c and I41/amd, respectively. The latter exhibits coinciding layer stacking as known from tetragonal HgI2. The T4 compounds close the gap between the longer known T2 types and the recently reported compounds with T5 and T6 supertetrahedra. Measurements of the optical band gap, electrical resistivity and Hall Effect support the semiconducting nature of M4Ga5SiAs9. Magnetization measurements confirm Eu2+ in Eu4Ga5SiAs9 and indicate ferromagnetism below T = 2 K.


2020 ◽  
Vol 75 (1-2) ◽  
pp. 201-208
Author(s):  
Christian Funk ◽  
Jürgen Köhler ◽  
Thomas Schleid

AbstractThe new Ruddlesden-Popper-related phases An+1BnO3n+1 (n = 3) with the compositions Li2Eu2Nb3O10, Li2Eu1.5Ta3O10, Li2EuKNb3O10, and Li2EuKTa3O10 were synthesized by solid-state reactions from Li2[CO3] (+ K2[CO3]) and the corresponding refractory metals along with their oxides in a high-frequency furnace at temperatures above T = 1600°C. Their structures have been determined by single-crystal X-ray diffraction studies. Characteristic features are triple layers of corner-sharing [MO6]7− octahedra (M = Nb and Ta), which are connected via [LiO4]7− tetrahedra. The Eu2+ cations are cuboctahedrally surrounded by 12 oxygen atoms and according to the Eu–O distances of around 275 pm, they have the oxidation state +2, as confirmed by XPS measurements. In the potassium-containing samples they share their positions with K+ cations. The black compounds are stable in air at room temperature. Measurements of the magnetic susceptibilities in the range of T = 5–300 K revealed Li2Eu2Nb3O10, Li2Eu1.5Ta3O10 and Li2EuKTa3O10 to be paramagnetic without any ordering.


1996 ◽  
Vol 51 (9) ◽  
pp. 1290-1294 ◽  
Author(s):  
Hk. Müller-Buschbaum

Two new alkaline earth vanadyl compounds, Sr2(VO)(AsO4)2 (I) and Ba2(VO)(PO4)2 (II), have been prepared by solid state reactions in closed quartz tubes and characterized by single crystal X-ray diffraction methods. Crystal data: (I): monoclinic, C62h -I2/a, a = 6.873(2), b = 16.307(4), c = 7.196(2) Å, β = 115.67(2), Z = 4; (II): monoclinic, C32-I2, a = 9.471(2), b = 5.443(1), c = 16.972(4) Å, β = 101.65(2), Z = 4. (I) is isotypic to Sr2(VO)V2O8 and Sr2(VO)(PO 4)2. (II) shows significant differences to the strontium compounds as well as to Ba2(VO)(VO4)2. The differences of the crystal chemistry and the similarity of (II) to Ba2(VO)(PO4)2 H2O are discussed.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Isabelle Georg ◽  
Michael Bolte ◽  
Matthias Wagner ◽  
Hans-Wolfram Lerner

Abstract The λ 6Si-silicate [Cs(18-crown-6)]2[Si(OSO2CH3)6] (1) was synthesized by treatment of Si2Cl6 with Cs[OSO2CH3] in the presence of 18-crown-6. Compound 1 is the first example of a λ 6Si-silicate with a methanesulfonate ligand. It was characterized by NMR spectroscopy and by single-crystal X-ray diffraction. The solid-state structure of 1 consists of discrete [Si(OSO2CH3)6]2– anions and two [Cs(18-crown-6)]+ cations (triclinic space group, P 1 ¯ $P\overline{1}$ , Z = 1).


1988 ◽  
Vol 66 (1) ◽  
pp. 123-131 ◽  
Author(s):  
William O. Nelson ◽  
Timothy B. Karpishin ◽  
Steven J. Rettig ◽  
Chris Orvig

A series of 3-hydroxy-2-methyl-4(1H)-pyridinones has been prepared with the substituents H, CH3, n-C6H11, and CH2CH2NH2 at the ring N. The dipyridinone 1,6-bis(3-hydroxy-2-methyl-4(1H)-pyridinon-1-yl)hexane has also been synthesized. The products with H and CH3 substituents have been studied by single crystal X-ray diffraction. Crystals of 3-hydroxy-2-methyl-4-pyridinone are monoclinic, a = 6.8351(4), b = 10.2249(4), c = 8.6525(4) Å, β = 105.215(4)°, Z = 4, space group P21/n and those of 3-hydroxy-1,2-dimethyl-4-pyridinone are orthorhombic, a = 7.3036(4), b = 13.0490(6), c = 13.7681(7) Å, Z = 8, space group Pbca. Both structures were solved by direct methods and were refined by full-matrix least-squares procedures to R = 0.037 and 0.044 for 914 and 857 reflections with I ≥ 3σ(I), respectively. Bond lengths and angles in the two compounds were normal. All the compounds have been studied by mass spectrometry, and by infrared and proton nmr spectroscopies. The importance of hydrogen bonding to both the solution and solid state properties of these compounds has been confirmed by these techniques.


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