Chemical element or an electrophile; similarly "Nu" denotes a nucleophile. "L" is used to represent a general ligand in inorganic and organometallic chemistry. "M" is also often used in place of a general metal. At least two additional, two-letter generic chemical symbols are also in informal usage, "Ln" for any lanthanide element and "An" for any actinide element. "Rg" was formerly used for any rare gas element, but the group of rare gases has now been renamed noble gases and the symbol "Rg" has now been assigned to the element roentgenium. Isotopes are distinguished by the atomic mass number (total protons and
Cobalt(II) oxide Cobalt(II) oxide Cobalt(II) oxide or cobalt monoxide is an inorganic compound that appears as olive-green to red crystals, or as a greyish or black powder. It is used extensively in the ceramics industry as an additive to create blue colored glazes and enamels as well as in the chemical industry for producing cobalt(II) salts. CoO crystals adopt the periclase (rock salt) structure with a lattice constant of 4.2615 Å. It is antiferromagnetic below 16 °C. Cobalt(II,III) oxide decomposes to cobalt(II) oxide at 950 °C: Though commercially available, cobalt(II) oxide may be prepared in the laboratory by electrolyzing a solution of