Structures of (ND4)2V(SO4)2.6D2O and (ND4)2V0.45Zn0.55(SO4)2.6D2O At 5.8 K by Neutron Diffraction

1988 ◽  
Vol 41 (9) ◽  
pp. 1289 ◽  
Author(s):  
RJ Deeth ◽  
BN Figgis ◽  
JB Forsyth ◽  
ES Kucharski ◽  
PA Reynolds
Keyword(s):  
Solid Solution ◽  
Neutron Diffraction ◽  
Bond Length ◽  
Crystal Structures ◽  
The Other ◽  
Tetragonal Distortion ◽  
X Ray Diffraction ◽  
Tutton Salts ◽  
X Ray

The crystal structures of (ND4)2V(SO4)2.6D2O and (ND4)2V0.45Zn0.55(SO4)2.6D2O have been determined at 5.8 K by neutron diffraction. The 663 and 857 unique reflections measured respectively refined to give R(F2) 0.035 and 0.045. The crystals are monoclinic, P21/a, isostructural with the other members of the series of Tutton salts. The V-O bond length of 211.8 pm [210.4 pm for mean (V/Zn)-O in the solid solution with Zn] is intermediate between these for the Mn (214.9 pm) and the Ni(205.5 pm) salts. It is shorter than the value determined by X-ray diffraction at 295 K. The major departure from a regular VO6 octahedron is a shortened V-O(9) bond, such as is observed in the other Tutton salts, to give a tetragonal distortion.

Compression and Compressibility Studies of Plutonium and a Plutonium-Gallium Alloy

1980 ◽  
Vol 24 ◽  
pp. 221-230 ◽  
Author(s):  
R. B. Roof
Keyword(s):  
Solid Solution ◽  
The Other ◽  
X Ray Diffraction ◽  
X Ray ◽  
Metal Foils ◽  
Gallium Alloy

Two metal foils, one pure plutonium and the other being a solid solution of 6.5 a/o gallium In plutonium, were examined, in-situ, by X-ray diffraction techniques while under pressure. The purpose was to determine the compression and compressibility of these materials as a function of pressure and to identify the products of any transformation that may occur due to the action of applied pressures.

Glass-Coated Cu-Mn-Ga Microwires Produced by Taylor-Ulitovsky Technique

2009 ◽  
Vol 152-153 ◽  
pp. 79-84 ◽  
Author(s):  
Joan Josep Suñol ◽  
L. Escoda ◽  
C. García ◽  
V.M. Prida ◽  
Victor Vega ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solid Solution ◽  
Curie Temperature ◽  
Energy Dispersive Spectroscopy ◽  
Room Temperature ◽  
Alloy Composition ◽  
The Other ◽  
X Ray Diffraction ◽  
X Ray ◽  
Low Magnetic Field

Glass-coated Cu-Mn-Ga microwires were fabricated by Taylor-Ulitovsky technique. By means of energy dispersive spectroscopy microanalysis, an average alloy composition of Cu56Ga28Mn16 was determined. The temperature dependence of magnetization measured at a low magnetic field showed the coexistence of two ferromagnetic phases. The Curie temperature of one phase is 125 K and above room temperature for the other one. X-ray diffraction at room temperature and at 100 K reflects the presence of the same three crystalline phases corresponding to the cubic B2 Cu-Mn-Ga structure as a main phase and the minor phases of fcc Cu rich solid solution with Mn and Ga and the monoclinic CuO.

scholarly journals Caracterização metalúrgica de ligas de Ni-Cr para metalocerimica

2021 ◽  
Vol 40 (1) ◽  
pp. 57-59
Author(s):  
Carlos Ariel Samudio Perez ◽  
Cezar Augusto Garbin
Keyword(s):  
Solid Solution ◽  
Diffraction Analysis ◽  
The Other ◽  
Secondary Phases ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hardness Tests ◽  
Density Values ◽  
Cubic Structure ◽  
Hardness Values

Alternative Ni-Cr alloys applied in dentistry of two commercial brands for ceramometal restoration were evaluated. The alloys were analyzed in the commercial and after casting conditions using experimental techniques of metallography, X-ray diffraction, superficial hardness and density. The metalografics and X-ray diffraction analysis showed that, the alloys microstructure is marked with the presence of a solid solution having an ordered face- centred cubic structure, Ni-rich austenitic (y phase) matrix, and with fine precipitates particles of secondary phases. The Vicker hardness tests showed a decrease in hardness values of the studied alloys aer casting. The alloys density values, on the other hand, did not manifest changes.

Synthesis and Crystal Structures of New 1,3-Disubstituted Imidazoline-2-thiones

2013 ◽  
Vol 68 (11) ◽  
pp. 1239-1252 ◽  
Author(s):  
Gerhard Laus ◽  
Volker Kahlenberg ◽  
Klaus Wurst ◽  
Thomas Müller ◽  
Holger Kopacka ◽  
...  
Keyword(s):  
Bond Length ◽  
Crystal Structures ◽  
1H Nmr ◽  
Significant Contribution ◽  
Resonance Structure ◽  
X Ray Diffraction ◽  
Reference Compound ◽  
X Ray ◽  
Hydrolysis Of ◽  
By Products

Two methods (MeOH/K2CO3, pyridine/Et3N) were assessed for the introduction of sulfur into the 2-position of 1,3-disubstituted quaternary imidazolium salts 1-9 (Cl, I, BF4, PF6, CH3OSO3 were used as anions) to yield nine 1,3-disubstituted imidazoline-2-thiones 10-18 (1, 10: R1 = CH3, R2 = CH3; 2, 11: R1 = OCH2Ph, R2 = CH3; 3, 12: R1 = OCH3, R2 = CH3; 4, 13: R1 = OCH3, R2 = OCH3; 5, 14: R1 = NH2, R2 = CH2Ph; 6, 15: R1 = NCHPh, R2 = CH3; 7, 16: R1 = NH2, R2 = CH3; 8, 17: R1 = NCHPh, R2 = NCHPh; 9, 18: R1 = NH2, R2 = OCH3). Compounds 11-18 represent N-alkyloxy and N-amino imidazoline-2-thiones, whereas 10 served as reference compound. The first method was advantageous for the conversion 1 → 10 due to faster reaction, whereas in the reaction 2 → 11 considerable amounts of by-products were formed. Pure thiones 11, 14, 16, 17, and 18 were obtained only by the second method. Both methods worked for the synthesis of the methoxy derivatives 12 and 13 from 3 and 4, and the benzylideneamino derivative 15 from 6. 1-Amino-3- methylimidazoline-2-thione (16) was also prepared by hydrolysis of the benzylideneamino derivative 15. Crystal structures of seven 1,3-disubstituted imidazoline-2-thiones were determined by singlecrystal X-ray diffraction. Intermolecular C-H···S contacts were identified and, additionally, N-H···S interactions in aminothiones 14 and 16. The 1H NMR shifts of 10 and 13 were satisfactorily correlated with the Kamlet-Abboud-Taft π* and b parameters in ten solvents. From the lack of correlation with the a parameter and from the C=S bond length (average 1.68 Å ) a significant contribution of a mesoionic imidazolium-2-thiolate resonance structure seems unlikely.

scholarly journals Bonding effects and the crystal structures of (NH4)2[Cu(H2O)6](SO4)2 and its H2 18O substituted form at 9.5 K

2000 ◽  
Vol 56 (3) ◽  
pp. 438-443 ◽  
Author(s):  
Brian N. Figgis ◽  
Alexandre N. Sobolev ◽  
Charles J. Simmons ◽  
Michael A. Hitchman ◽  
Horst Stratemeier ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Crystal Structures ◽  
X Ray Diffraction ◽  
Tutton Salts ◽  
X Ray ◽  
Distorted Octahedral ◽  
Structural Differences ◽  
Jahn Teller ◽  
Normal Water ◽  
Water Ligands

The crystal structures of the Tutton salts (NH4)2-[Cu(H2O)6](SO4)2, diammonium hexaaquacopper disulfate, formed with normal water and isotopically substituted H2 18O, have been determined by X-ray diffraction at 9.5 K and are very similar, with Cu—O(7) the longest of the Cu—O bonds of the Jahn–Teller distorted octahedral [Cu(H2O)6]2+ complex. It is known that structural differences accompany deuteration of (NH4)2[Cu(H2O)6](SO4)2, the most dramatic of which is a switch to Cu—O(8) as the longest such bond. The present result suggests that the structural differences are associated with hydrogen-bonding effects rather than with increased mass of the water ligands affecting the Jahn–Teller coupling. The Jahn–Teller distortions and hydrogen-bonding contacts in the compounds are compared with those reported for other Tutton salts at ambient and high pressure.

Crystallographic studies of BaR2ZnO5 (R=La, Nd, Dy, Ho, Er, and Y)

1998 ◽  
Vol 13 (3) ◽  
pp. 144-151 ◽  
Author(s):  
Winnie Wong-Ng ◽  
Brian Toby ◽  
William Greenwood
Keyword(s):  
Neutron Diffraction ◽  
Crystal Structures ◽  
Lattice Parameters ◽  
Trigonal Prism ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters

The crystal structures of BaR2ZnO5, where R=La, Nd, Dy, Ho, and Y, were studied by neutron diffraction, and that of the Er analog was investigated by synchrotron X-ray diffraction. Two structure types were confirmed for this series of compounds and agreed with those reported in literature. The compounds with a smaller size of R (R=Dy, Ho, Y, and Er) are isostructural to the orthorhombic “green phase (BaY2CuO5)” compounds. The cell parameters for compounds with the R=Er to Dy range from a=7.0472(1) Å to 7.0944(1) Å, b=12.3022(1) Å to 12.3885(2) Å, and c=5.6958(1) Å to 5.7314(1) Å, respectively. R is 7-fold coordinated inside a monocapped trigonal prism. These prisms share edges to form wavelike chains parallel to the long b-axis. The Ba atoms reside in 11-fold coordinated cages. The compounds which contain a larger size R (R=La and Nd) crystallize in the tetragonal I4/mcm space group, but are not isostructural to the “brown phases” BaR2CuO5. The lattice parameters for the La and Nd analogs are a=6.9118(1) Å, c=11.6002(2) Å for BaLa2ZnO5, and a=6.7608(1) Å and c=11.5442(2) Å for BaLa2ZnO5. The structure consists of ZnO4 tetrahedral groups (instead of planar CuO4 groups as found in the brown phase) with Ba ions inserted in between. The structure can be viewed as consisting of alternate layers of Zn-Ba-O and Nd-O extending infinitely in the xy plane and perpendicular to the z-axis.

Torsional vibration and central bond length of N-benzylideneanilines

2004 ◽  
Vol 60 (5) ◽  
pp. 578-588 ◽  
Author(s):  
Jun Harada ◽  
Mayuko Harakawa ◽  
Keiichiro Ogawa
Keyword(s):  
Temperature Dependence ◽  
Bond Length ◽  
Crystal Structures ◽  
Torsional Vibration ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
Static Disorder ◽  
X Ray ◽  
Bond Lengths ◽  
Central Bond

The crystal structures of N-benzylideneaniline (1), N-benzylidene-4-carboxyaniline (2), N-(4-methylbenzylidene)-4-nitroaniline (3), N-(4-nitrobenzylidene)-4-methoxyaniline (4), N-(4-nitrobenzylidene)-4-methylaniline (5), N-(4-methoxybenzylidene)aniline (6) and N-(4-methoxybenzylidene)-4-methylaniline (7) were determined by X-ray diffraction analyses at various temperatures. In the crystal structures of all the compounds, an apparent shortening of the central C=N bond was observed at room temperature. As the temperature was lowered, the observed bond lengths increased to approximately 1.28 Å at 90 K, irrespective of substituents in the molecules. The shortening and the temperature dependence of the C=N bond length are interpreted in terms of an artifact caused by the torsional vibration of the C—Ph and N—Ph bonds in the crystals. In the crystal structures of (1) and (7), a static disorder around the C=N bond was observed, which is also responsible for the apparent shortening of the C=N bond.

Neutron and X-ray Diffraction Study on the Structure of Ultraphosphate Glasses

1997 ◽  
Vol 52 (3) ◽  
pp. 259-269 ◽  
Author(s):  
Uwe Hoppe ◽  
Günter Walter ◽  
Dörte Stachel ◽  
Andrea Barz ◽  
Alex C. Hannon
Keyword(s):  
Crystal Structures ◽  
Coordination Number ◽  
Real Space ◽  
The Other ◽  
Oxide Content ◽  
X Ray Diffraction ◽  
X Ray ◽  
Space Resolution ◽  
Epithermal Neutrons ◽  
The Mean

Abstract The high real-space resolution of neutron diffraction experiments which is provided by use of the epithermal neutrons from spallation sources was exploited in order to differentiate the unlike P-O bonds existing in the PO4 units of phosphate glass networks. The 2 P-O distance peaks, separated by about 12 pm, which were found in the zinc and the calcium ultraphosphate glasses studied are assigned to oxygen sites on bridging (OB) and terminal (OT) positions. The mean P-O distances are nearly invariable versus the growing metal oxide content which results from an elongation of the P-OB and P-OT bonds. The bond lengths which are known from the related crystal structures and from ab initio calculations show almost the same behaviour. The discussion of further details of the crystal structures leads to the conclusion that P-OB rather than P-OT distances should show more details in case of diffraction measurements of even higher real-space resolution. The change of the Zn-O coordination number from 6 to 4 versus increasing ZnO content, which was obtained in previous X-ray diffraction experiments, is confirmed by the recent combination of neutron and X-ray diffraction data. On the other hand, the Ca-O coordination number of about 6 is almost invariable.

Sign in / Sign up

Export Citation Format

Share Document