Metalloid what classification criteria are used. Emsley recognised four metalloids (germanium, arsenic, antimony, and tellurium); James et al. listed twelve (Emsley's plus boron, carbon, silicon, selenium, bismuth, polonium, moscovium, and livermorium). On average, seven elements are included in such lists; individual classification arrangements tend to share common ground and vary in the ill-defined margins. A single quantitative criterion such as electronegativity is commonly used, metalloids having electronegativity values from 1.8 or 1.9 to 2.2. Further examples include packing efficiency (the fraction of volume in a crystal structure occupied by atoms) and the Goldhammer-Herzfeld criterion ratio. The commonly recognised metalloids have packing
Germanium disulfide is restricted to fumaroles of some burning coal-mining waste heaps. 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