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Other selenium allotropes may contain Se 6 or Se 7 rings. [15] The most stable and dense form of selenium is gray and has a chiral hexagonal crystal lattice (space group 152 or 154 depending on the chirality) [19] consisting of helical polymeric chains, where the Se–Se distance is 237.3 pm and Se–Se–Se angle is 103.1°. The minimum ...
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Selenium Remote Control was a refactoring of Driven Selenium or Selenium B designed by Paul Hammant, credited with Jason as co-creator of Selenium. The original version directly launched a process for the browser in question, from the test language of Java, .NET, Python or Ruby.
[1] [2] [3] Selenium belongs with oxygen and sulfur to the group 16 elements or chalcogens, and similarities in chemistry are to be expected. Organoselenium compounds are found at trace levels in ambient waters, soils and sediments. [4] Selenium can exist with oxidation state −2, +2, +4, +6. Se(II) is the dominant form in organoselenium ...
Selenocysteine is present in several enzymes (for example glutathione peroxidases, tetraiodothyronine 5′ deiodinases, thioredoxin reductases, formate dehydrogenases, glycine reductases, selenophosphate synthetase 2, methionine-R-sulfoxide reductase B1 , and some hydrogenases).
Selenium compounds are compounds containing the element selenium (Se). Among these compounds, selenium has various oxidation states , the most common ones being −2, +4, and +6. Selenium compounds exist in nature in the form of various minerals, such as clausthalite , guanajuatite , tiemannite , crookesite etc., and can also coexist with ...
The isotope selenium-75 has radiopharmaceutical uses. For example, it is used in high-dose-rate endorectal brachytherapy, as an alternative to iridium-192. [8]In paleobiogeochemistry, the ratio in amount of selenium-82 to selenium-76 (i.e, the value of δ 82/76 Se) can be used to track down the redox conditions on Earth during the Neoproterozoic era in order to gain a deeper understanding of ...
All group 7 elements crystallize in the hexagonal close packed (hcp) structure except manganese, which crystallizes in the body centered cubic (bcc) structure. Bohrium is also expected to crystallize in the hcp structure. [1] The table below is a summary of the key physical properties of the group 7 elements. The question-marked value is ...