Praseodymium Selenide

See more Praseodymium products. Praseodymium (atomic symbol: Pr, atomic number: 59) is a Block F, Group 3, Period 6 element with an atomic weight of 140.90765. The number of electrons in each of praseodymium's shells is 2, 8, 18, 21, 8, 2 and its electron configuration is [Xe]4f³ 6s². The praseodymium atom has a radius of 182 pm and a Van der Waals radius of 239 pm. Praseodymium resembles the typical trivalent rare earths, however, it will exhibit a +4 state when stabilized in a zirconia host. Unlike other rare-earth metals, which show antiferromagnetic and / or ferromagnetic ordering at low temperatures, praseodymium is paramagnetic at any temperature above 1 K. Praseodymium is found in the minerals monazite and bastnasite. Praseodymium was discovered by Carl Auer von Welsbach in 1885. The origin of the element name comes from the Greek words prasios didymos, meaning green twin.

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.