Tungsten Selenide Flakes

See more Selenium products. Selenium (atomic symbol: Se, atomic number: 34) is a Block P, Group 16, Period 4 element with an atomic radius of 78.96. The number of electrons in each of Selenium's shells is 2, 8, 18, 6 and its electron configuration is [Ar] 3d¹⁰ 4s² 4p⁴. The selenium atom has a radius of 120 pm and a Van der Waals radius of 190 pm. Selenium is a non-metal with several allotropes: a black, vitreous form with an irregular crystal structure three red-colored forms with monoclinic crystal structures and a gray form with a hexagonal crystal structure, the most stable and dense form of the element. One of the most common uses for selenium is in glass production the red tint that it lends to glass neutralizes green or yellow tints from impurities in the glass materials. Selenium was discovered and first isolated by Jöns Jakob Berzelius and Johann Gottlieb Gahn in 1817. The origin of the name Selenium comes from the Greek word "Selênê," meaning moon.

See more Tungsten products. Tungsten (atomic symbol: W, atomic number: 74) is a Block D, Group 6, Period 6 element with an atomic weight of 183.84. The number of electrons in each of tungsten's shells is [2, 8, 18, 32, 12, 2] and its electron configuration is [Xe] 4f¹⁴ 5d⁴ 6s². The tungsten atom has a radius of 139 pm and a Van der Waals radius of 210 pm. Tungsten was discovered by Torbern Bergman in 1781 and first isolated by Juan José Elhuyar and Fausto Elhuyar in 1783. In its elemental form, tungsten has a grayish white, lustrous appearance. Tungsten has the highest melting point of all the metallic elements and a density comparable to that or uranium or gold and about 1.7 times that of lead. Tungsten alloys are often used to make filaments and targets of x-ray tubes. It is found in the minerals scheelite (CaWO₄) and wolframite [(Fe,Mn)WO₄]. In reference to its density, Tungsten gets its name from the Swedish words tung and sten, meaning heavy stone.