Germanium Germanium Germanium is a chemical element with symbol Ge and atomic number 32. It is a lustrous, hard, grayish-white metalloid in the carbon group, chemically similar to its group neighbors tin and silicon. Pure germanium is a semiconductor with an appearance similar to elemental silicon. Like silicon, germanium naturally reacts and forms complexes with oxygen in nature. Because it seldom appears in high concentration, germanium was discovered comparatively late in the history of chemistry. Germanium ranks near fiftieth in relative abundance of the elements in the Earth's crust. In 1869, Dmitri Mendeleev predicted its existence and some of its properties
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