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Following rearrangement and loss of water, a second equivalent of water attacks the alpha position. Red amorphous selenium is liberated in the final step to give the 1,2-dicarbonyl product. [8] [9]: 4331 Allylic oxidation using selenium-dioxide proceeds via an ene reaction at the electrophilic selenium center.
Sample of cadmium selenide, a pigment. The parent inorganic selenide is hydrogen selenide (H 2 Se). It is a colorless, malodorous, toxic gas. It dissolves in aqueous solution, to give the hydrogenselenide or biselenide ion HSe −. At higher pH, selenide forms. Solutions of hydrogen selenide and selenide are oxidized by air to give elemental ...
Selenium is found in metal sulfide ores, where it substitutes for sulfur. Commercially, selenium is produced as a byproduct in the refining of these ores. Minerals that are pure selenide or selenate compounds are rare. The chief commercial uses for selenium today are glassmaking and pigments. Selenium is a semiconductor and is used in photocells.
Selenium, like manganese, can be used in small concentrations to decolorize glass, or in higher concentrations to impart a reddish color, caused by selenium nanoparticles dispersed in glass. It is a very important agent to make pink and red glass. When used together with cadmium sulfide, [9] it yields a brilliant red color known as "Selenium Ruby".
The selenium cycle is a biological cycle of selenium similar to the cycles of carbon, nitrogen, and sulfur. Within the cycle, there are organisms which reduce the most oxidized form of the element and different organisms complete the cycle by oxidizing the reduced element to the initial state.
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.
Short title: example derived form Ghostscript examples: Image title: derivative of Ghostscript examples "text_graphic_image.pdf", "alphabet.ps" and "waterfal.ps"
In bacteria, the SECIS element is typically located immediately following the UGA codon within the reading frame for the selenoprotein. [17] In Archaea and in eukaryotes, the SECIS element is in the 3′ untranslated region (3′ UTR) of the mRNA and can direct multiple UGA codons to encode selenocysteine residues. [18]