Nonmetal inconsistently classified by different authors. Elements sometimes also classified as nonmetals are the metalloids boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), tellurium (Te), and astatine (At). The nonmetal selenium (Se) is sometimes instead classified as a metalloid, particularly in environmental chemistry. Nonmetals show more variability in their properties than do metals. These properties are largely determined by the interatomic bonding strengths and molecular structures of the nonmetals involved, both of which are subject to variation as the number of valence electrons in each nonmetal varies. Metals, in contrast, have more homogenous structures and their properties are more
Tellurium hexafluoride Tellurium hexafluoride Tellurium hexafluoride is a chemical compound of tellurium and fluorine with the chemical formula TeF. It is a colorless, highly toxic gas with an extremely unpleasant smell. Tellurium hexafluoride is most commonly prepared by passing fluorine gas over tellurium at 150 °C. Below this temperature a mixture of lower fluorides form, including tellurium tetrafluoride and ditellurium decafluoride. It can also be prepared by passing fluorine gas over TeO or indirectly by reacting TeO with SeF to produce TeF and then heating TeF in excess of 200 °C to make TeF and Te. Tellurium hexafluoride is a highly symmetric