Selenium Oxygen Research Articles

Unimolecular rearrangement of the simplest compound models with a selenium–oxygen, selenium–sulphur and selenium–selenium bond: SeXH and HSeXH (X = O,S,Se)

ABSTRACTThe aim of this study was to characterise the simplest compound models with a selenium–oxygen, selenium–sulphur and selenium–selenium bond as the SeXH and HSeXH isomers (X = O,S,Se). One of the main aspects of this investigation was to provide a description on the isomerisation pathways involving 2[H,Se,X] and 1[2H,Se,X] potential energy surfaces calculated at the CCSD(T)/CBS//MP2/cc-pVTZ level. The energy difference was 13 kcal mol−1 between hydroxyselenide (SeOH) and oxoselenium (HSeO), while a gap of 3 kcal mol−1 was predicted between thiol-selenide (SeSH) and selenol-sulphide (HSeS). The SeOH→HSeO unimolecular rearrangement showed a barrier energy of 44.6 kcal mol−1, decreasing almost two times in sulphur and selenium analogous reactions. In addition, hydroxyselenide (HSeOH), thioselenenic acid (HSeSH) and diselane (HSeSeH) were the global minimum configurations in the ground state, while the energy differences among the other isomers were close to 30 kcal mol−1. The HSeXH→H2SeX and HSeXH→SeXH2 isomerisations showed barrier energies ranging from 40 to 65 kcal mol−1, while these reverse routes presented heights that were three times smaller. The kinetic rate constant of each 1,2-H shift reaction was performed here as well as an analysis of the selenium-chalcogen bonds using natural bond orbital and bond order index methodologies.

Application of IMA to the analysis of oxygen in selenium

The applicability of IMA to the analysis of oxygen in selenium was studied. In order to prevent the sample charge-up, the electron spraying technique was applied. A calibration curve of the secondary ion intensity ratio I( 16O −) I( 80Se −) was obtained by analysing oxygen doped selenium samples. The detection limit of oxygen has been estimated as 20 ppm.

Application of IMA to the analysis of oxygen in selenium

Application of IMA to the analysis of oxygen in selenium

Determination of oxygen in selenium, tellurium and their compounds

Determination of oxygen in selenium, tellurium and their compounds

Radiochemical determination of oxygen traces in selenium

A sensitive method for determination of oxygen in selenium is described. Oxygen is converted into the gaseous compound sulfur dioxide labelled with35S. The β-radiation of35S is measured by liquid scintillation counting. The detection limit is 0.02 ppm. The efficiency of vacuum distillation in the purification of selenium, and the influence of air, dry oxygen and water on the absorption of oxygen by selenium have been investigated.

ESR Study of the Behaviour of Oxygen in Selenium

ESR Study of the Behaviour of Oxygen in Selenium

Interaction of sodium admixtures and oxygen in selenium

Interaction of sodium admixtures and oxygen in selenium