The Vapor Density of Selenium Tetrabromide and the Existence of Selenium Dibromide

Abstract

The adiabatic (London) theory of reaction rates has been applied, for the first time, to reactions involving four atoms. It shows, unambiguously, that the thermal reaction of hydrogen with iodine will involve only iodine molecules, while the other halogens will react with hydrogen by way of the atoms. It shows further that the conversion of para to ortho hydrogen will involve an atom and a molecule rather than two molecules. It explains the well-known greater reactivity of the heavy halogen compounds over the lighter ones. These checks with experiment are independent of the ratio of coulombic to total binding except in the case of bromine. If the known theoretical ratio of coulombic to total binding for hydrogen is assumed to hold for the other atoms, approximate agreement with experiment is obtained. To obtain exact agreement in the reaction EL + L = 2HI the coulombic binding must be assumed to be only three and a half per cent, of the total binding. The theoretical evaluation of the coulombic binding is possible, but difficult, using the approximate eigenfunctions of

The molecular structure of selenium dibromide as determined by combined gas-phase electron diffraction–mass spectrometric experiments and quantum chemical calculations

“…In 1937 Yost and Hatcher measured the vapour pressure over SeBr 4 and established that it disproportionates to SeBr 2 and Br 2 in the vapour phase. 7 The gas-phase structure of the vapour over SeBr 4 was studied by Akishin, Spiridonov and Mishulina in 1962. 8 It was suggested that the sample of SeBr 4 (s) decomposed and analysis of the GED intensities yielded a value of r(Se-Br) = 2.32 AE 2 A ˚.…”

Phasenbeziehungen im System SeBr und die Kristallstrukturen des dimorphen SeBr4

“…: , 9 ( 3 ) 0,2023 (15) 0,0328(15) 0,36OC (9) 0,0092 ( 20) 0,1885 (19) 0,2531 ( 9 ) -S e ( n 1 ) -S e ( n 1 ) -S e ( n 1 ) -S e ( n 1 ) -S e ( n 1 ) -S e ( n 1 ) -S e ( n 1 ) -S e ( n 1 ) -S e ( n 1 ) -S e ( n 1 ) -S e ( n l 1 -S e ( n 1 )…”