Theoretical Enthalpies of Formation of CHmCln:  Neutral Molecules and Cations

1996 ◽  
Vol 100 (8) ◽  
pp. 2942-2949 ◽  
Author(s):  
Christopher F. Rodriquez ◽  
Diethard K. Bohme ◽  
Alan C. Hopkinson
Keyword(s):  
Enthalpies Of Formation

Calorimetrie an Yttriumtrihalogeniden und Yttriumoxidhalogemden / Calorimetry of Yttrium Trihalides and Yttrium Oxyhalides

1997 ◽  
Vol 52 (3) ◽  
pp. 305-310 ◽  
Author(s):  
H. Oppermann ◽  
S. Ehrlich ◽  
C. Hennig
Keyword(s):  
Enthalpies Of Formation ◽  
Heats Of Solution

Abstract The heats of solution of Yttrium, YOCL, YOBr, YOI, YCl3, YBr3, YI3 and Y2O3 were determined in 4n HX. From those the enthalpies of formation of Yttrium Trihalides YX3 and Yttrium Oxyhalides YOX at 298 K were derived: ΔHB0(YCl3,f,298) = -240.4 ± 0.6 kcal/mol, ΔHB0(YBr3,f,298) = -202.1 ± 1.5 kcal/mol,ΔHB0(YI3,f ,298) = -147.0 ± 1.7 kcal/mol, ΔHB0(YOClf,298) = -240.2 ± 1.0 kcal/mol, ΔHB0(YOBrf,298) = -229.7 ± 2.0 kcal/mol, ΔHB0(YOIf ,298) = -208.8 ± 2.0 kcal/mol.

Crystal structure and lattice energetics of 10-methylacridinium halides

2000 ◽  
Vol 53 (8) ◽  
pp. 627 ◽  
Author(s):  
Piotr Storoniak ◽  
Karol Krzyminski ◽  
Pawel Dokurno ◽  
Antoni Konitz ◽  
Jerzy Blazejowski
Keyword(s):  
Crystal Lattice ◽  
Lattice Energy ◽  
Enthalpies Of Formation ◽  
Triclinic Space Group ◽  
X Ray ◽  
Molecular Arrangement ◽  
Van Der Waals Contacts ◽  
Chloride Monohydrate ◽  
Insight Into

The crystal structures of 10-methylacridinium chloride monohydrate, bromide monohydrate and iodide were determined by X-ray analysis. The compounds crystallize in the triclinic space group, P¯1, with 2 molecules in the unit cell. The molecular arrangement in the crystals revealed that hydrogen bonds (in hydrates) and van der Waals contacts play a significant part in intermolecular interactions. To discover their nature, contributions to the crystal lattice energy arising from electrostatic (the most important since the compounds form ionic crystals), dispersive and repulsive interactions were calculated. Enthalpies of formation of the salts, their stability and susceptibility to decomposition could be predicted from a combination of crystal lattice energies with values of other thermochemical characteristics obtained theoretically or taken from the literature. The role of water in the stabilization of the crystal lattice of the hydrates is also explained. The information gathered has given an insight into the features and behaviour of compounds which can be regarded as models of a large group of aromatic quaternary nitrogen salts.

Standard molar enthalpies of formation of some methylfuran derivatives

2010 ◽  
Vol 100 (2) ◽  
pp. 375-380 ◽  
Author(s):  
Manuel A. V. Ribeiro da Silva ◽  
Luísa M. P. F. Amaral
Keyword(s):  
Enthalpies Of Formation

Thermochemistry of Organic and Heteroorganic Species. Part IX. Photoionization Studies of Isomerization and Fragmentation of Polysubstituted Cyclopropenes: Phenyl-Substituted Cyclopropenes

2000 ◽  
Vol 6 (1) ◽  
pp. 53-64 ◽  
Author(s):  
V.V. Takhistov ◽  
I.N. Domnin ◽  
D.A. Ponomarev
Keyword(s):  
Mass Spectrometry ◽  
Enthalpy Of Formation ◽  
Good Alternative ◽  
Enthalpies Of Formation ◽  
Isodesmic Reactions ◽  
Ion Structure ◽  
Photoionization Mass Spectrometry ◽  
General Methodology ◽  
Fragment Ions ◽  
The Enthalpy Of Formation

Ionization and appearance energies of some fragment ions from 1,2,3-trimethy1-3-phenyl-, 3-methyl-1,2,3-triphenyl-, 1,2-diphenyl-3-methoxycarbonyl-, 1,2,3-triphenyl-3-methoxycarbonyl- and 1,3,3-triphenyl-2-methoxycarbonyl-cyclopropenes were measured by photoionization mass spectrometry. It was shown that in none of these compounds did the fragment ions possess the expected stable substituted cyclopropenium ion structure. Accordingly, possible schemes of molecular ion isomerization are given. The enthalpies of formation of nearly 50 substituted cyclopropenium ions, and ions of related structure, were estimated using series of isodesmic reactions. This publication, together with the previous works of the authors in this Journal, demonstrates the general methodology for estimation of the enthalpy of formation for even-electron ions. It is suggested that the present methodology can provide a good alternative to other estimation or computation procedures applied to the thermochemistry of ions.

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