Die Molekülstruktur des N-Chlorsdiwefeloxiddifluoridimids ClNSOF2 / The Molecular Structure of ClNSOF2

1974 ◽  
Vol 29 (6) ◽  
pp. 901-904 ◽  
Author(s):  
O. Oberhammer ◽  
O. Glemser ◽  
H. Klüver
Keyword(s):  
Molecular Structure ◽  
Electron Diffraction ◽  
Geometric Parameters ◽  
Mean Square ◽  
The Mean

The molecular structure of ClNSOF2 was determined by electron diffraction of gases. The following geometric parameters were obtained:Cl-N=1.715(5), S=N=1.484(7), S=O=1.394(3), S-F=1.548(3) Å, ∢ ClNS=114.7 (8), ∢ FSF=92.6(.8), ∢ NSF=111.8(.9) ∢ NSO=117.4 (3.1) and ∢ OSF=108.6 (.8)°. The results for the mean square amplitudes of vibration are given in the paper and an attempt is made to explain differences in corresponding parameters of some related molecules.

Molekūlstrukturen von Phoshorverbindungen / Molecular Structure of Phosphorus Compounds. 1. Trimethylphosphate

1973 ◽  
Vol 28 (7) ◽  
pp. 1140-1144
Author(s):  
I. Trimethylphosphat ◽  
H. Oberhammer
Keyword(s):  
Molecular Structure ◽  
Electron Diffraction ◽  
Vapour Phase ◽  
Geometric Parameters ◽  
Phosphorus Compounds ◽  
Mean Square ◽  
Scattering Intensity ◽  
Rotational Isomers ◽  
Best Fit

The molecular structure of Trimethylphosphate O = P(OCH3)3 has been determined in the vapour phase by electron diffraction. The best fit of the experimental scattering intensity was obtained by assuming two rotational isomers with C3-symmetry occuring in a ratio of approximately 3:1. The geometric parameters and mean square amplitudes are given in the article.

Molekülstrukturen von Phosphorverbindungen, IV / Molecular Structures of Phosphorus Compounds, IV

1975 ◽  
Vol 30 (7-8) ◽  
pp. 506-512 ◽  
Author(s):  
H. Oberhammer ◽  
J. Grobe
Keyword(s):  
Electron Diffraction ◽  
Geometric Parameters ◽  
Molecular Structures ◽  
Trigonal Bipyramid ◽  
Phosphorus Compounds ◽  
Equatorial Position ◽  
Mean Square ◽  
Potential Barriers ◽  
Distorted Trigonal Bipyramid ◽  
The Mean

The molecular structures of the two trifluoromethyl phosphoranes (CF3)2PCl3 and (CF3)3PCl2 have been determined by electron diffraction of gases. The structure of (CF3)2PCl3 was found to be a regular trigonal bipyramid with both CF3 groups in axial positions (D3h symmetry) and the fluorine atoms staggered to the equatorial chlorine atoms. The following geometric parameters (ra-values) were obtained: r(C-F) = 1.331(2) Å, r(P-C) = 1.950(II) Å, r(P-Cl) = 2.036(2) Å and ⦓ FCF = 108.3°(0.4). (CF3)3PCl2 possesses the structure of a distorted trigonal bipyramid with two CF3 groups in axial and one in equatorial position. Again the fluorine atoms of the axial CF3 groups are staggered to the equatorial atoms. The ra-values for the geometric parameters are: r(C-F)= 1.329(2) Å, r(P-C)eq= 1.938(31) Å, r(P-C)ax = 1.946(14) Å, r(P-Cl) = 2.053(6) Å, ⦓ FCF = 108.5°(0.3), ⦓ ClPCl = 133.0°(1.7) and ⦓ CaxPCeq = 95.5°(1.9). The average P-C bond length was found to be r(P-C)av = 1.943(5) A. The results for the mean square amplitudes are given in the article. It was shown that in both molecules the torsional amplitudes of the CF3 groups around the P-C bond directions are small, indicating high potential barriers to internal rotation.

The Molecular Structure of 2-Methyloxacyclobutane, as Studied by Electron Diffraction

1979 ◽  
Vol 34 (9) ◽  
pp. 1130-1134 ◽  
Author(s):  
György Schultz ◽  
Mihály Bartók
Keyword(s):  
Molecular Structure ◽  
Carbon Atom ◽  
Electron Diffraction ◽  
Electron Diffraction Study ◽  
Membered Ring ◽  
Torsional Angle ◽  
Planar Conformation ◽  
The Mean ◽  
Nozzle Temperature ◽  
Endocyclic Bond

Abstract A gas electron diffraction study of 2-methyloxacyclobutane has been carried out at room nozzle temperature. The four membered ring takes a planar conformation. The mean ra values for the O-C, C-C and C-H bonds are 1.448(5)A, 1.534(4)A and 1.118(3) Å, respectively. The endocyclic bond angles are C-C-C = 85.5(18)° and C-C-O=91.2 (15)°, while the angle C-O-C was assumed to be 92°. The position of exocyclic carbon atom was characterized, in addition by < Cexocyclic-C-O = 110.7(7)° and torsional angle Cexocyclic-C-O-C = 59.6(40)° (0° corresponds to the anti position of Cexocyclic-C and O-C bonds).

Notizen:Electron Diffraction Investigation of the Molecular Structure of Trifluoromethyl Sulphonyl Chloride

1978 ◽  
Vol 33 (10) ◽  
pp. 1236-1238 ◽  
Author(s):  
Jon Brunvoll ◽  
István Hargittai ◽  
Mária Kolonits
Keyword(s):  
Molecular Structure ◽  
Electron Diffraction ◽  
Geometric Parameters ◽  
Electron Diffraction Investigation

Abstract An electron diffraction investigation yielded the following geometric parameters for trifluoromethyl sulphonyl chloride rg(C-F ) 1.326(4), rg(S=0 ) 1.416(7), rg(S-Cl) 2.016(5), rg(S-C) 1.857(6) Å, ∢ O= S - C 108.3(7)°, ∢ C-S-Cl 98.7(4)°, ∢ O = S = O 122.4(10),° ∢ O = S - Cl 108.3(3)°, ∢ F -C-F 109.9(3)°. The S - C bond is in CF3SO2Cl by almost 0.1 Å longer than in CH3SO2Cl.

The Molecular Structure of Trimethylindium by Vapor Phase Electron Diffraction

1974 ◽  
Vol 52 (23) ◽  
pp. 3936-3940 ◽  
Author(s):  
Gerald Barbe ◽  
J. Lawrence Hencher ◽  
Quang Shen ◽  
Dennis G. Tuck
Keyword(s):  
Molecular Structure ◽  
Electron Diffraction ◽  
Root Mean Square ◽  
Vapor Phase ◽  
Axial Symmetry ◽  
Structural Parameters ◽  
Phase Factor ◽  
Methyl Groups ◽  
Mean Square ◽  
Shrinkage Effect

The molecular structure of trimethylindium has been redetermined by vapor phase electron diffraction. The independent structural parameters assuming three-fold axial symmetry based on the rg distances and their estimated uncertainties (2σ) are r(InC) = 209.3 ± 0.6 pm, r(CH) = 114 ± 3 pm, and < HCIn = 112.7 ± 0.8°. A slight nonplanarity (3.0 ± 2.5°) was attributed to a shrinkage effect in [Formula: see text] of 0.4 pm. The analysis was insensitive to the rotational position of the methyl groups relative to the InC3 frame. The root mean square amplitudes were not accurate due to a problem with the indium phase factor.

The Molecular Structure and Hydrogen Bond Geometry in Liquid Formamide: Electron, Neutron, and X-Ray Diffraction Studies

1983 ◽  
Vol 38 (2) ◽  
pp. 231-236 ◽  
Author(s):  
E. Kálmán ◽  
I. Serke ◽  
G. Pálinkás ◽  
M. D. Zeidler ◽  
F. J. Wiesmann ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Hydrogen Bond ◽  
Electron Diffraction ◽  
Diffraction Data ◽  
Free Molecule ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Mean ◽  
Diffraction Patterns ◽  
Good Agreement

Abstract Electron, neutron and X-ray diffraction patterns of liquid formamide have been measured at a temperature of 25 °C. Analysis of the diffraction data yields the molecular structure and the average geometry of the hydrogen bond. The molecular parameters obtained from liquid diffraction experiments are in good agreement with those from gas electron diffraction for the free molecule. The mean O…N and O…H hydrogen bond distances are 2.9 Å and 1.9 Å, respectively. Four H-bonds per molecule are found on the average. The deviation of the H-bonds from the linearity is estimated.

scholarly journals Notizen:The G eneralised Mean Square Amplitudes of Vibration for Substituted Ethylenes Vinylidene Halides and their Deuterates

1971 ◽  
Vol 26 (4) ◽  
pp. 778-780
Author(s):  
S. Jeyapandian
Keyword(s):  
Electron Diffraction ◽  
Diffraction Data ◽  
Spectroscopic Data ◽  
Electron Diffraction Data ◽  
Mean Square ◽  
Type C ◽  
The Mean

Abstract For six vinylidene halides the generalised mean square amplitudes of displacements parallel and perpendicular to the bond for both bonded and non-bonded atom distances are cal­culated from spectroscopic data using the method of Morino and Hirato. The results are discussed and the mean amplitu­des of these molecules (H2C=CX2) are compared with those from electron diffraction data for the similar molecules of the type C2X4.

Die Molekülstruktur des Trifluorsilylphosphans (F3SiPH2) / Molecular Structure of Trifluorosilylphosphane (F3SiPH2)

1973 ◽  
Vol 28 (11) ◽  
pp. 1862-1865 ◽  
Author(s):  
R. Demuth ◽  
H. Oberhammer
Keyword(s):  
Molecular Structure ◽  
Electron Diffraction ◽  
Gas Phase ◽  
Structural Parameters ◽  
Bond Distance ◽  
The Other ◽  
Mean Square

The molecular structure of trifluorosilylphosphane in the gas phase has been determined by electron diffraction. A short P -Si bond distance of 2.207 (3) Å as compared to other investigated silysphosphanes was found for this molecule. The other structural parameters and mean square amplitudes are given in the article.

The Bordeaux Automatic Meridian Circle

1978 ◽  
Vol 48 ◽  
pp. 227-228
Author(s):  
Y. Requième
Keyword(s):  
Mean Square Error ◽  
Mean Square ◽  
Meridian Circle ◽  
The Mean ◽  
Full Automation

In spite of important delays in the initial planning, the full automation of the Bordeaux meridian circle is progressing well and will be ready for regular observations by the middle of the next year. It is expected that the mean square error for one observation will be about ±0.”10 in the two coordinates for declinations up to 87°.

Isomorphous replacement in electron diffraction of wet crystals of rat hemoglobin

1983 ◽  
Vol 41 ◽  
pp. 446-447
Author(s):  
William F. Tivol ◽  
Murray Vernon King ◽  
D. F. Parsons
Keyword(s):  
Electron Diffraction ◽  
Heavy Atom ◽  
Isomorphous Substitution ◽  
X Ray Diffraction ◽  
Salt Solutions ◽  
X Ray ◽  
Isomorphous Replacement ◽  
Structure Factors ◽  
Diffraction Structure ◽  
The Mean

Feasibility of isomorphous substitution in electron diffraction is supported by a calculation of the mean alteration of the electron-diffraction structure factors for hemoglobin crystals caused by substituting two mercury atoms per molecule, following Green, Ingram & Perutz, but with allowance for the proportionality of f to Z3/4 for electron diffraction. This yields a mean net change in F of 12.5%, as contrasted with 22.8% for x-ray diffraction.Use of the hydration chamber in electron diffraction opens prospects for examining many proteins that yield only very thin crystals not suitable for x-ray diffraction. Examination in the wet state avoids treatments that could cause translocation of the heavy-atom labels or distortion of the crystal. Combined with low-fluence techniques, it enables study of the protein in a state as close to native as possible.We have undertaken a study of crystals of rat hemoglobin by electron diffraction in the wet state. Rat hemoglobin offers a certain advantage for hydration-chamber work over other hemoglobins in that it can be crystallized from distilled water instead of salt solutions.

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