Silicon by inflammation and scarring in the form of nodular lesions in the upper lobes of the lungs. Silicon Silicon is a chemical element with symbol Si and atomic number 14. It is a hard and brittle crystalline solid with a blue-grey metallic lustre; and it is a tetravalent metalloid and semiconductor. It is a member of group 14 in the periodic table: carbon is above it; and germanium, tin, and lead are below it. It is relatively unreactive. Because of its large chemical affinity for oxygen, it was not until 1823 that Jöns Jakob Berzelius was first able to prepare
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