scholarly journals The crystal structure of copper sulphate pentahydrate, CuSO 4 .5H 2 O

1934 ◽  
Vol 146 (858) ◽  
pp. 570-582 ◽  
Keyword(s):  
Crystal Structure ◽  
Copper Sulphate ◽  
The Other ◽  
Large Numbers ◽  
Points Of View

Despite their frequent appearance in the laboratory, few of the structures of hydrated salts have as yet been found. This may be due to the large numbers of parameters usually involved, which, in the absence of any general laws concerning water of crystallization, makes the analysis very difficult. It was thought that clues to such general laws might be obtained from a determination of the structure of copper sulphate pentahydrate which has many interesting properties and which has been studied from many different points of view. For example, the decomposition on heating proceeds in three distinct stages, CuSO 4 .5H 2 O→CuSO 4 . 3H 2 O→CuSO 4 . H 2 O→CuSO 4 , reactions which should be explainable from a knowledge of the structure. Also, four of the waters are replaceable by ammonias, while the other one is retained. This suggests that one of the waters is very different from the others.

Simultaneous determination of trace elements in serum by energy-dispersive x-ray fluorescence spectrometry.

1984 ◽  
Vol 30 (8) ◽  
pp. 1300-1303 ◽  
Author(s):  
F Rastegar ◽  
E A Maier ◽  
R Heimburger ◽  
C Christophe ◽  
C Ruch ◽  
...  
Keyword(s):  
Analytical Procedure ◽  
Internal Standard ◽  
Detection Limits ◽  
The Other ◽  
Energy Dispersive ◽  
Statistical Distributions ◽  
Polypropylene Film ◽  
X Ray ◽  
Large Numbers

Abstract Energy-dispersive x-ray fluorescence is applied in the analysis of human serum to determine the concentrations of several elements simultaneously with minimal manipulation of the sample. The analytical procedure has been developed with standard sera, and standardization, detection limits, and reproducibility have been established. A 50-microL sample of diluted serum, to which an internal standard has been added, is deposited on a thin (4-microns thick) polypropylene film and analyzed by x-ray fluorescence. We report the statistical distributions of the concentrations of Fe, Cu, Zn, and Br obtained in the population (103 samples) studied, and report detection limits for the other 22 elements studied. The simplicity of the method, the high throughput, and the possibility of automating the measurements make this procedure suitable for screening large numbers of sera.

Crystal structure and stereoisomerism of Tris(O-ethylxanthato)antimony(III) in its lattice hemiadduct with 4,4'-bipyridyl

1978 ◽  
Vol 31 (4) ◽  
pp. 757 ◽  
Author(s):  
DL Kepert ◽  
CL Raston ◽  
AH White ◽  
G Winter
Keyword(s):  
Crystal Structure ◽  
Structure Determination ◽  
Electron Pair ◽  
Complex Molecule ◽  
Lone Pair ◽  
Antimony Atom ◽  
The Other ◽  
Mirror Plane ◽  
Crystallographic Symmetry

The preparation and crystal structure determination of the adduct [Sb(S2COEt)3],0.5C10H8N2 is reported. Crystals are triclinic, Pī, a 6.064(3), b 10.825(6), c 17.723(7) Ǻ, α 104.77(4), β 96.78(3), γ 97.14(4)°, Z 2. The compound is a lattice adduct, the bipyridyl molecule being located about a crystallographic centre of symmetry. The complex molecule geometry is unlike that of the compound [Sb(S2COEt)3]; in the latter the molecule has crystallographic symmetry 3, the three equivalent ligands being unsymmetrically coordinated, while in the present molecule the chirality is lost, the molecule conforming to approximate pseudo-m symmetry: two ligands are similar [Sb-S, 2.615(2), 2.892(2); 2.612(2), 2.878(2) Ǻ] and the other, located in the pseudo-mirror plane, is different [Sb-S, 2.477(2), 3.091(2) Ǻ]. Electron-pair repulsion theory shows that the bond angles, the relative bond lengths, and the coexistence of different stereoisomers of this molecule, can be ascribed to the stereochemically active lone pair of electrons being close to the antimony atom.

Planar distributions of dislocations III. The exact positions of important dislocations when the number in an array is large

1971 ◽  
Vol 320 (1543) ◽  
pp. 527-535 ◽  
Keyword(s):  
Simple Procedure ◽  
Continuous Distribution ◽  
The Other ◽  
General Situation ◽  
Burgers Vector ◽  
Large Numbers ◽  
Discrete Dislocations ◽  
Model Determination ◽  
Exact Positions

It is shown that if large numbers of complete dislocations are piled-up against a coplanar barrier dislocation, the equilibrium positions occupied by those discrete dislocations in the immediate vicinity of the barrier can be found directly from the characteristics, in the barrier’s neighbourhood, of the function representing the situation where all the dislocations are smeared into a continuous distribution, assuming that they have the same Burgers vector. Since such characteristics are readily obtained by examining the relevant singular integral equation for the model, determination of the important dislocation positions becomes a simple procedure. The approach is exact and refers to the limiting situation where the number of dislocations is very large; on the other hand, the smeared-discrete compromise approach (described in earlier papers in this series), in which the important dislocations remain discrete while the remainder are smeared into a continuous distribution, is approximate but is applicable to the more general situation where the number of dislocations is sufficiently large for the distance between the important dislocations to be small compared with the array length.

Reaktionen von 1,2,4-Thiadiazol-3,5-dicarbonitril mit Schwefelchloriden: Röntgenstrukturanalyse von S3(CN)4Cl2·AsF5 und S3(CN)8Cl2/Reactions of 1,2,4-Thiadiazol-3,5-dicarbonitrile with Sulfur Chlorides: X-Ray Crystal Structure Analysis of S3(CN)4Cl2·A sF5 and S3(CN)8Cl2

1986 ◽  
Vol 41 (2) ◽  
pp. 162-166 ◽  
Author(s):  
Herbert W. Roesky ◽  
Jörg Sundermeyer ◽  
Jürgen Schimkowiak ◽  
Thomas Gries ◽  
Mathias Noltemeyer ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Nitrogen Atom ◽  
Sulfur Atom ◽  
Experimental Error ◽  
Crystal Structure Analysis ◽  
The Other ◽  
Space Group ◽  
X Ray ◽  
Ring Nitrogen

The reactions between 1,2,4-thiadiazol-3,5-dicarbonitrile, S(CN)4, and sulfur chlorides (SCl2 and S2Cl2) in the presence of Adogen® 464 (Aldrich) proceeds with formation of S3(CN)4Cl2 (1) and S3(CN)8Cl2 (2). These main products were characterized by X-ray structure determination of an adduct 1a and of 2. This adduct 1a was obtained by addition of the Lewis acid AsF5 in liquid SO2. 1a crystallizes with one SO2 molecule in the space group P21/n with a = 1177.3(2), b = 1082.8(1), c = 1255.3(5) pm, β = 109.73(3)°, Z = 4, V = 1.5061 nm3. It contains two five-membered rings connected by a nitrogen atom. AsF5 is coordinated to one of the ring nitrogen atoms [N(1)] adjacent to the sulfur atom S(1) and C(1)Cl-group. The other ring contains an S(2)-S(3) bond of length 207.7(4) pm. The rings are planar within experimental error. 2 crystallizes in the space group P21/n with a = 782.12(6), b = 1498.1(5), c = 1217.8(2) pm, β = 102.43(1)°, Z = 4, V = 1.3934 nm3. 2 is formed by addition of one molecule of SCl2 to two molecules of S(CN)4.

Methylzinn- und Methylindium-bis(trimethylsilyl)amide / Methyltin and Methylindium Bis(trimethylsilyl)amides

1991 ◽  
Vol 46 (4) ◽  
pp. 459-467 ◽  
Author(s):  
Michael Rannenberg ◽  
Johann Weidlein ◽  
Axel Obermeyer
Keyword(s):  
Crystal Structure ◽  
Structure Determination ◽  
Homologous Series ◽  
Nmr Spectra ◽  
The Other ◽  
Crystal Structure Determination ◽  
New Compounds

BrSn[N(SiMe3)2]3 and ClIn[N(SiMe3)2]2 react with LiMe · O(C2H5)2 (Me = CH3) in toluene or hexane to give the corresponding amido derivatives MeM[N(SiMe3)2]x (M = Sn, x = 3 and M = In, x = 2). These new compounds and the other members of the homologous series MenM[N(SiMe3)2]4 or 3-n are characterized by their IR, Raman und NMR spectra. In addition, the results of the crystal structure determination of MeSn[N(SiMe3)2]3 are reported.

scholarly journals Pirquitasite, Ag2ZnSnS4

2013 ◽  
Vol 69 (2) ◽  
pp. i8-i9 ◽  
Author(s):  
Benjamin N. Schumer ◽  
Robert T. Downs ◽  
Kenneth J. Domanik ◽  
Marcelo B Andrade ◽  
Marcus J. Origlieri
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
General Formula ◽  
Diffraction Data ◽  
The Other ◽  
Tetragonal Symmetry ◽  
X Ray Diffraction ◽  
X Ray ◽  
Anisotropic Displacement Parameters

Pirquitasite, ideally Ag2ZnSnS4(disilver zinc tin tetrasulfide), exhibits tetragonal symmetry and is a member of the stannite group that has the general formulaA2BCX4, withA= Ag, Cu;B= Zn, Cd, Fe, Cu, Hg;C= Sn, Ge, Sb, As; andX= S, Se. In this study, single-crystal X-ray diffraction data are used to determine the structure of pirquitasite from a twinned crystal from the type locality, the Pirquitas deposit, Jujuy Province, Argentina, with anisotropic displacement parameters for all atoms, and a measured composition of (Ag1.87Cu0.13)(Zn0.61Fe0.36Cd0.03)SnS4. One Ag atom is located on Wyckoff site Wyckoff 2a(symmetry -4..), the other Ag atom is statistically disordered with minor amounts of Cu and is located on 2c(-4..), the (Zn, Fe, Cd) site on 2d(-4..), Sn on 2b(-4..), and S on general site 8g. This is the first determination of the crystal structure of pirquitasite, and our data indicate that the space group of pirquitasite isI-4, rather thanI-42mas previously suggested. The structure was refined under consideration of twinning by inversion [twin ratio of the components 0.91 (6):0.09 (6)].

scholarly journals Redetermination of nickel(II) formate dihydrate

IUCrData ◽  
2018 ◽  
Vol 3 (3) ◽  
Author(s):  
Matthias Weil
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Structure Determination ◽  
Three Dimensional ◽  
The Other ◽  
Water Molecules ◽  
Hydrogen Bonding Pattern ◽  
Medium Strength

In comparison with the previous structure determination of poly[diaquadi-μ-formato-nickel(II)], [Ni(HCOO)2(H2O)2]n, based on Weissenberg film data [Krogmann & Mattes (1963).Z. Kristallogr.118, 291–302], the current redetermination from modern CCD data revealed the positions of the H atoms, thus making a detailed description of the hydrogen-bonding pattern possible. Both Ni2+cations in the crystal structure are located on inversion centres and are octahedrally coordinated. One Ni2+cation is bound to six O atoms of six formate anions whereas the other Ni2+cation is bound to four O atoms of water molecules and to two formate O atoms. In this way, the formate anions bridge the two types of Ni2+cations into a three-dimensional framework. O—H...O hydrogen bonds of medium strength between water molecules and formate O atoms consolidate the packing.

Zur Chemie der 1,3,5-Triaza-2-phosphorinan-4,6-dione. Teil IX. Umsetzungen einiger 1,3,5-Triorgano-1,3,5-triaza-2λ3-phosphorinan-4,6-dione mit Hexafluoraceton / Chemistry of the 1,3,5-Triaza-2-phosphorinan-4,6-diones. Part IX. Reaction of some 1,3,5-Triorgano-1,3,5-triaza-2λ3-phosphorinan-4,6-diones with Hexafluoroacetone

1995 ◽  
Vol 50 (12) ◽  
pp. 1785-1790 ◽  
Author(s):  
Ion Neda ◽  
Michael Farkens ◽  
Axel K. Fischer ◽  
Peter G. Jones ◽  
Reinhard Schmutzler
Keyword(s):  
Crystal Structure ◽  
Phosphorus Atom ◽  
Mass Spectra ◽  
Membered Ring ◽  
The Other ◽  
X Ray ◽  
Trigonal Bipyramidal ◽  
Phosphoryl Compound ◽  
Spirocyclic Compounds

The reactions of 2-(2-chloroethyl)amino-1,5-dimethyl-3-phenyl-1,3,5-triaza-2λ3-phosphorinan- 4,6-dione (1), 2-bis(2-chloroethyl)amino-1,5-dimethyl-3-phenyl-1,3,5-triaza-2A3-phosphorinan- 4,6-dione (2), 2-methoxy-1,3,5-trimethyl-1,3,5-triaza-2λ3-phosphorinan-4,6-dione (3) and 2-trimethylsiloxy-1,3,5-trimethyl-1,3,5-triaza-2λ3-phosphorinan-4,6-dione (5) with hexafluoracetone are described. In the case of 2 and 3 the reaction furnished the spirocyclic compounds 7 and 8. 2-Bis(2-chloroethyl)amino-1,3,5-triphenyl-1,3,5-triaza-2λ3-phosphorinan- 4,6-dione (4) did not react. In the case of 1 and 5 rearrangement reactions took place; the (2-chloroethyl)amino substituent of 1 reacted with one of two equivalents of hexafluoroacetone with formation of the spirocyclic phosphorane 6. The reaction of 5 with tetrabromoorthobenzoquinone gave the phosphoryl compound 9. Compounds 6 - 8 were characterized via their 1H-, 13C-, 19F- and 31P-NMR and mass spectra, compound 9 via its 1H-, 13C- and 31P-NMR and mass spectra. An X-ray crystal structure determination of 8 was conducted; in the six-membered ring the phosphorus atom lies 73 pm out of the plane of the other atoms, and displays trigonal bipyramidal coordination.

388. The colorimetric determination of lactic acid in milk and milk products

1949 ◽  
Vol 16 (2) ◽  
pp. 209-216 ◽  
Author(s):  
J. Davidson
Keyword(s):  
Lactic Acid ◽  
Calcium Hydroxide ◽  
Copper Sulphate ◽  
Colorimetric Determination ◽  
Colour Intensity ◽  
Purple Colour ◽  
Milk Products ◽  
Fresh Milk ◽  
Large Numbers

A method is described for the colorimetric determination of lactic acid in milk and unsweetened milk products. The protein and lactose is removed after precipitation with copper sulphate and calcium hydroxide at 45° C, the lactic acid in an aliquot of the filtrate is oxidized to acetaldehyde in sulphuric acid in the presence of copper sulphate, a purple colour is developed with p–hydroxydiphenyl, and the colour intensity is measured in a photoelectric absorptiometer or other suitable instrument.Recoveries of from 96 to 103%, averaging 100%, were obtained when 20–400 mg. lactic acid/100 ml. were added to fresh milk.The proposed method has an advantage over existing methods in the ease and speed with which large numbers of determinations can be carried out simultaneously whilst retaining the essential accuracy.

Lincoln and the Negro

2017 ◽  
Author(s):  
Arna Bontemps
Keyword(s):  
Abraham Lincoln ◽  
The Other ◽  
American Colonization Society ◽  
Moral Principles ◽  
The People ◽  
Large Numbers ◽  
Points Of View

This chapter discusses the role of Abraham Lincoln in the fight against slavery in Illinois. Among the people who abhorred slavery were some who objected to having large numbers of Negroes for neighbors. Two types of anti-slavery sentiment arose, one based upon moral principles and the other upon economic principles. There were those who advocated abolition to elevate the Negro to citizenship and those who objected to slavery merely because it was an economic evil. This chapter considers the divided opinion on the problem of the freed Negro, led by the American Colonization Society, who disseminated propaganda against the Negro, and Lincoln, who was sympathetic toward the plan to colonize freed Negroes. It also examines how Lincoln, an astute politician, steered a course midway between the two points of view, and concludes with a look at his friendship with William de Fleurville of Springfield.

Sign in / Sign up

Export Citation Format

Share Document