Nonmetal are called "metalloids" mainly in light of their physical resemblance to metals. While they each have a metallic appearance, they are brittle and only fair conductors of electricity. Boron, silicon, germanium, tellurium are semiconductors. Arsenic and antimony have the electronic band structures of semimetals although both have less stable semiconducting allotropes. Astatine has been predicted to have a metallic crystalline structure. Chemically the metalloids generally behave like (weak) nonmetals. They have moderate ionisation energies, low to high electron affinities, moderate electronegativity values, are poor to moderately strong oxidising agents, and demonstrate a tendency to form alloys with metals. The reactive
Germanium disulfide Germanium disulfide Germanium disulfide or Germanium(IV) sulfide is the inorganic compound with the formula GeS. It is a white high-melting crystalline solid. The compound is a 3-dimensional polymer, in contrast to silicon disulfide, which is a one-dimensional polymer. The Ge-S distance is 2.19 Å. Germanium disulfide was the first germanium compound found by Clemens Winkler, during the analysis of argyrodite. The fact that germanium sulfide does not dissolve in aqueous acid made it possible for Winkler to isolate the new element. Germanium disulfide is created by reacting hydrogen sulfide with germanium tetrachloride in a concentrated hydrochloric acid solution. Natural GeS