Holmium(III) Selenate

See more Holmium products. Holmium (atomic symbol: Ho, atomic number: 67) is a Block F, Group 3, Period 6 element with an atomic radius of 164.93032. The number of electrons in each of Holmium's shells is [2, 8, 18, 29, 8, 2] and its electron configuration is [Xe] 4f¹¹ 6s². The holmium atom has a radius of 176 pm and its Covalent radius is 192±7 pm. Holmium was first discovered by Marc Delafontaine in 1878. In its elemental form, holmium has a silvery white appearance. It is relatively soft and malleable. It is stable in dry air at room temperature but rapidly oxidizes at elevated temperatures and in moist air. Holmium has unusual magnetic properties. Its name is derived from the Latin word Holmia meaning Stockholm.

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.