scholarly journals Crystal structure, homogeneity range and electronic structure of rhombohedral γ-Mn5Al8

Author(s):  
Srinivasa Thimmaiah ◽  
Zachary Tener ◽  
Tej N. Lamichhane ◽  
Paul C. Canfield ◽  
Gordon J. Miller

AbstractThe γ-region of the Mn–Al phase diagram between 45 and 70 at.% Al was re-investigated by a combination of powder and single crystal X-ray diffraction as well as EDS analysis to establish the distribution of Mn and Al atoms. Single crystals of γ-Mn

IUCrData ◽  
2019 ◽  
Vol 4 (11) ◽  
Author(s):  
Artem V. Malin ◽  
Sergei I. Ivlev ◽  
Roman V. Ostvald ◽  
Florian Kraus

Single crystals of rubidium tetrafluoridobromate(III), RbBrF4, were grown by melting and recrystallizing RbBrF4 from its melt. This is the first determination of the crystal structure of RbBrF4 using single-crystal X-ray diffraction data. We confirmed that the structure contains square-planar [BrF4]− anions and rubidium cations that are coordinated by F atoms in a square-antiprismatic manner. The compound crystallizes in the KBrF4 structure type. Atomic coordinates and bond lengths and angles were determined with higher precision than in a previous report based on powder X-ray diffraction data [Ivlev et al. (2015). Z. Anorg. Allg. Chem. 641, 2593–2598].


2004 ◽  
Vol 82 (2) ◽  
pp. 301-305 ◽  
Author(s):  
Kenneth CW Chong ◽  
Brian O Patrick ◽  
John R Scheffer

When crystals of 9-tricyclo[4.4.1.0]undecalyl-4-(carbomethoxy)phenyl ketone (1) were allowed to stand in the dark for extended periods of time at room temperature, the compound underwent a thermal reaction — the enolene rearrangement — to afford enol 2. The crystals remained transparent and appeared unchanged in shape as the reaction proceeded. X-ray diffraction data were collected on single crystals containing 17%, 25%, 66%, and 100% of the enol. The crystal structure of a simple enol was obtained via this novel single-crystal-to-single-crystal enolene rearrangement.Key words: single crystal, thermal, rearrangement, enol, enolene.


2015 ◽  
Vol 71 (11) ◽  
pp. 1325-1327 ◽  
Author(s):  
Maxim Bykov ◽  
Elena Bykova ◽  
Vadim Dyadkin ◽  
Dominik Baumann ◽  
Wolfgang Schnick ◽  
...  

Hitherto, phosphorus oxonitride (PON) could not be obtained in the form of single crystals and only powder diffraction experiments were feasible for structure studies. In the present work we have synthesized two polymorphs of phosphorus oxonitride, cristobalite-type (cri-PON) and coesite-type (coe-PON), in the form of single crystals and reinvestigated their crystal structures by means of in house and synchrotron single-crystal X-ray diffraction. The crystal structures ofcri-PON andcoe-PON are built from PO2N2tetrahedral units, each with a statistical distribution of oxygen and nitrogen atoms. The crystal structure of thecoe-PON phase has the space groupC2/cwith seven atomic sites in the asymmetric unit [two P and three (N,O) sites on general positions, one (N,O) site on an inversion centre and one (N,O) site on a twofold rotation axis], while thecri-PON phase possesses tetragonalI-42dsymmetry with two independent atoms in the asymmetric unit [the P atom on a fourfold inversion axis and the (N,O) site on a twofold rotation axis]. In comparison with previous structure determinations from powder data, all atoms were refined with anisotropic displacement parameters, leading to higher precision in terms of bond lengths and angles.


2011 ◽  
Vol 66 (11) ◽  
pp. 1087-1091 ◽  
Author(s):  
Olaf Reckeweg ◽  
Francis J. DiSalvo

Colorless and transparent single crystals of Ba2H3I were obtained by reacting Ba with dried and sublimed NH4I in a 4 : 1 molar ratio in silica-jacketed Nb ampoules at 1100 K for 13 h. The crystal structure of the title compound was determined and refined by means of single-crystal X-ray diffraction. Ba2H3I crystallizes in a stuffed anti-CdI2 structure isotypic to Sr2H3I in the space group P3̄m1 (no. 164) with the lattice parameters a = 451.86(12) and c = 811.84(23) pm. The structural results for Ba2H3I are consistent with bond lengths and coordination geometries of related binary and ternary hydrides


1983 ◽  
Vol 38 (7) ◽  
pp. 830-834 ◽  

Abstract Single crystals of acetyltetralone grown from a solution containing a small amount of Cu(II) ions are studied by ESR. The corresponding g, 63Cu magnetic and quadrupolar hyperfine tensors are obtained and are consistent with the trapping of a square planar copper(II) complex. X-ray diffraction shows that pure acetyltetralone crystallizes in the orthorhombic space group Pbca (a - 8.893 Å, b = 20.301 Å, c = 10.715 Å). Comparison of the ESR eigenvectors with the bond directions obtained from this crystal structure study shows that the Cu(II) complex experiences some constraint from the crystal matrix. The present complex is a model for one of the complexation sites of tetracyclines.


Author(s):  
L. Bohatý ◽  
R. Fröhlich

AbstractKZnSbTN is an example from the large acentric double salt-like family of tartrato-antimonates. Its crystal structure was determined from single-crystal X-ray diffraction data (orthorhombic,Single crystals of the title compound of up to 4×4×6 cm


1975 ◽  
Vol 30 (3-4) ◽  
pp. 277-278 ◽  
Author(s):  
Hans-L. Keller ◽  
Karl-H. Meier ◽  
Hk. Müller-Buschbaum

Single crystals of SrPbO3 could be prepared by oxygen-high-pressure-synthesis (PO2 > 3500 at, t = 450°C). Single crystal X-ray diffraction data confirm the space group D2h16-Pnma. SrPbO3 belongs to the orthorhombic distorted Perowskit type with a = 5.964, b = 8.320, c = 5.860 Å. The atomic positions were refined.


2003 ◽  
Vol 58 (9) ◽  
pp. 929-933 ◽  
Author(s):  
Jochen Glaser ◽  
Ruth Schmitt ◽  
H.-Jürgen Meyer

Cr3C2 was obtained from arc-melting of pellets made of carbon and chromium. The structure of Cr3C2 was determined by single crystal X-ray diffraction (Pnma, Z = 4, a = 553.99(6), b = 283.27(4), c = 1149.4(1) pm, R1 = 0.019 and wR2 = 0.037 for all collected reflections). The crystal structure contains isolated carbon atoms which reside inside of trigonal prismatic voids of metal atoms. The compound exhibits temperature independent paramagnetism. The electronic structure of Cr3C2 has been investigated using extended Hückel calculations.


IUCrData ◽  
2020 ◽  
Vol 5 (7) ◽  
Author(s):  
Holger Lars Deubner ◽  
Sergei I. Ivlev ◽  
Florian Kraus

Single crystals of trichloridosulfonium(IV) hexachloridouranate(V) were obtained from the reaction of uranium(IV) chloride with an excess of disulfur dichloride and studied by single-crystal X-ray diffraction. In comparison with the structure model reported previously [Sawodny et al. (1983). Z. Anorg. Allg. Chem. 499, 81–88.], the lattice parameters and fractional atomic coordinates were determined to a much higher precision, leading overall to an improved structure model. The ionic compound contains trigonal–pyramidal (SCl3)+ cations and slightly distorted octahedral [UCl6]− anions. The structure was refined as an inversion twin with a twin ratio of 4.4:1.


IUCrData ◽  
2018 ◽  
Vol 3 (5) ◽  
Author(s):  
Sergei I. Ivlev ◽  
Florian Kraus

Single crystals of K[BrF4], potassium tetrafluoridobromate(III), were grown from a solution of KHF2 in bromine trifluoride. The current report is the first refinement of the crystal structure of K[BrF4] using single-crystal X-ray diffraction data. In comparison with previous refinements from powder data, the fractional coordinates of the F atom were determined with higher precision, and anisotropic displacement parameters were refined for all atoms. The structure contains square-planar [BrF4]− anions. The coordination polyhedron of the potassium cation is a square antiprism.


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