Metalloid Metalloid A metalloid is a type of chemical element which has properties in between, or that are a mixture of, those of metals and nonmetals. There is neither a standard definition of a metalloid nor complete agreement on the elements appropriately classified as such. Despite the lack of specificity, the term remains in use in the literature of chemistry. The six commonly recognised metalloids are boron, silicon, germanium, arsenic, antimony, and tellurium. Five elements are less frequently so classified: carbon, aluminium, selenium, polonium, and astatine. On a standard periodic table, all eleven elements are located in a diagonal region of
Arsenic pentachloride Arsenic pentachloride Arsenic pentachloride is a chemical compound of arsenic and chlorine. This compound was first prepared in 1976 through the UV irradiation of arsenic trichloride, AsCl, in liquid chlorine at −105 °C. AsCl decomposes at around −50 °C. The structure of the solid was finally determined in 2001. AsCl is similar to phosphorus pentachloride, PCl in having a trigonal bipyramidal structure where the equatorial bonds are shorter than the axial bonds (As-Cl = 210.6 pm, 211.9 pm; As-Cl= 220.7 pm). The pentachlorides of the elements above and below arsenic in group 15, phosphorus pentachloride and antimony pentachloride are much