Metalloids
A metalloid is a chemical element with properties in between, or that are a mixture of, those of metals and nonmetals. There is no standard definition of a metalloid, nor is there complete agreement as to which elements are appropriately classified as such. Metalloids are usually too brittle to have any structural uses. They and their compounds are used in alloys, biological agents, catalysts, flame retardants, glasses, optical storage and optoelectronics, pyrotechnics, semiconductors, and electronics