Group 9 element Rhodium, iridium, and meitnerium have no known biological roles. Group 9 element Group 9, numbered by IUPAC nomenclature, is a group of chemical element in the periodic table. Members are cobalt (Co), rhodium (Rh), iridium (Ir) and perhaps also the chemically uncharacterized meitnerium (Mt). These are all transition metals in the d-block. All known isotopes of meitnerium are radioactive with short half-lives, and it is not known to occur in nature; only minute quantities have been synthesized in laboratories. Like other groups, the members of this family show patterns in electron configuration, especially in the outermost shells, resulting in trends
Cobalt glass Cobalt glass Cobalt glass—known as "smalt" when ground as a pigment—is a deep blue colored glass prepared by including a cobalt compound, typically cobalt oxide or cobalt carbonate, in a glass melt. Cobalt is a very intense glass colorant and very little is required to show a noticeable amount of color. Cobalt blue glass is also used as an optical filter in flame tests to filter out the yellow flame caused by contamination with sodium, and expand the ability to see violet and blue hues. Moderately ground cobalt glass (potassium cobalt silicate)—called "smalt"—has been historically important as a pigment in