Selenium Granular X-Ray Degree Se Oxigen-Free 99.999% Purity

Selenium is a non-metal (or semi-metal) element (also known as a semi-metal). It belongs to Group 16 (Group VIA) of the periodic table and lies between sulfur and tellurium. Selenium has various allotrope forms, including gray, red, and black selenium. It is mainly found in sulfide ores of other metals and is obtained as a by-product (for example, from the anode sludge in electrolytic refining).
The chemical properties of selenium are similar to those of sulfur. Selenium reacts directly or in aqueous solutions with metals and many non-metals. It does not react directly with hydrogen fluoride or hydrogen chloride, but decomposes hydrogen iodide to release iodine and form hydrogen selenide. The appearance, composition, and properties of selenides are similar to those of sulfides. It can form halides by reacting vigorously with fluorine and chlorine, but its reaction with bromine and iodine is not as rapid. It reacts with oxygen to form many oxides, of which the most stable is selenium dioxide. Selenium was discovered by Berzelius and Gahn in 1817 during their study of the lead sulfate process. They initially believed that the unpleasant smell produced at the bottom of the lead chamber was due to the presence of tellurium, which was a sulfur group element discovered 35 years earlier. Further research indicated a new element with chemical properties very similar to tellurium. This new element was named selenium, derived from the Greek word selene, meaning moon. The name has been used for tellus, the Latin word representing tellurium, which is chemically similar to the new element. Willoughby Smith discovered the photoresistivity of this metal in 1873, that is, as the exposure intensity on the metal increases, its current resistance decreases.