The monomer-dimer self-association equilibrium of 2,2-dimethyl-3-ethyl-3pentanol in n-octane has been studied by IR spectroscopy at four temperatures (288, 298, 308, and 318 K). The solute was chosen to restrict the self-association between solute molecules to dimerization only, owing to steric hindrance of the bulky chains in the vicinity of the OH group. Two linear equations have been derived for the treatment of the experimental data. One of these equations was used to treat the data of the concentration dependent integrated absorbance of the monomer bands for each temperature to obtain the monomer molar absorptivity, e m , and dimerization constant, K. The other equation was used to treat the data of concentration-dependent dimer bands to obtain the dimer molar absorptivity, e d , and K. Thus, the dimerization constant was determined by two methods. Since the same thermodynamic quantity K is obtained from either the monomer bands or the dimer bands, the difference between them at a given temperature can serve as an assessment of the quality of the experiment. The standard enthalpy and entropy of dimerization were also obtained from a van't Hoff plot.
A stable molecule Li 2 H 2 has been identified experimentally and its stability determined.The gas species over solutions of hydrogen in liquid lithium were detected by mass spectrometric analysis of the saturated vapor effusing from a Knudsen cell. From the measurements of the gaseous equilibria Li 2 H 2 (g) + Li2(g) = 2Li 2 H(g), Li 2 H 2 (g) + Li(g) = LiH 2 (g) + Li 2 (g), Li 2 H 2 (g) + Li 2 (g) = Li3(g) + LiH 2 (g) andLi 2 H 2 (g) + LiH(g) = Li 2 H(g) + LiH 2 (g), an atomization energy D°O (Li 2 H 2 )= 164.3 ± 10 kcal/ mol and a heat of dimerization ΔH°O = -(52.6 ± 10) kcal/mol was obtained.Much theoretical work has been carried out on the lithium hydride molecule, which has become the workbench of the theoretical chemist CO, Browne 02), and Fraga and Ransil (3) have given the binding energy for the LiH + ion by ab initio calculation; Companion^) has applied the diatomic-in-molecule theory to the LiJA and LiH 2 molecules and predicted the stabilities of these molecules. We have intensively studied the Li-H system by means of Knudsen effusion mass spectrometry, and identified all predicted molecules and ions as cited above(5), and reported the thermochemical properties of these gaseous species (6, 7^, 8).The existence of a stable molecule Li 2 H 2 has not been demonstrated experimentally prior to this investigation, Tyndall and Companion(9) have studied the stability of ^n^2 ^ application of diatomics-in-molecules theory and given following heats of reaction: 0 2LiH( Z ) -> Li H0 ( B, ) AH n = -28.4 kcal/mol 2 2 lg 0 0097-6156/82/0179-0265$05.00/0
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.