title: Germanium tetrafluoride
text: # Germanium tetrafluoride
  
  Germanium tetrafluoride $(GeF_4)$ is a chemical compound of germanium and fluorine. It is a colorless gas.
  
  ## Synthesis
  
  Germanium tetrafluoride is formed by treating germanium with fluorine:
  
      Ge + 2 $F_2$ → $GeF_4$
  
  Alternatively germanium dioxide combines with hydrofluoric acid (HF):
  
      $GeO_2$ + 4 HF → $GeF_4$ + 2 $H_2O$
  
  It is also formed during the thermal decomposition of a complex salt, $Ba[GeF_6]:$
  
      $Ba(GeF_6)$ → $GeF_4$ + $BaF_2$
  
  ## Properties
  
  Germanium tetrafluoride is a noncombustible, strongly fuming gas with a garlic-like odor. It reacts with water to form hydrofluoric acid and germanium dioxide. Decomposition occurs above 1000 °C.
  
  Reaction of $GeF_4$ with fluoride sources produces $GeF_5^−$ anions with octahedral coordination around Ge atom due to polymerization. The structural characterization of a discrete trigonal bipyramidal $GeF_5^−$ anion was achieved by a "naked" fluoride reagent 1,3-bis(2,6-diisopropylphenyl)imidazolium fluoride.
  
  ## Uses
  
  In combination with disilane, germanium tetrafluoride is used for in the synthesis of SiGe.
  
  