Related compounds Boiling point -65 °C Density 1.66 g/cm³ | Formula SiF4 Molar mass 104.0791 g/mol | |
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Appearance colourless gas, fumes in moist air | ||
Silicon tetrafluoride sif4 lewis dot structure
Silicon tetrafluoride or Tetrafluorosilane is the chemical compound with the formula SiF4. This tetrahedral molecule is notable for having a remarkably narrow liquid range (its boiling point is only 4 °C above its melting point). It was first synthesized by John Davy in 1812.
Contents
Preparation
SiF
4 is a by-product of the production of phosphate fertilizers, resulting from the attack of HF (derived from fluorapatite protonolysis) on silicates, which are present as impurities in the phosphate rock. In the laboratory, the compound is prepared by heating BaSiF
6 above 300 °C, whereupon the solid releases volatile SiF
4, leaving a residue of BaF
2. The required BaSiF
6 is prepared by treating aqueous hexafluorosilicic acid with barium chloride. The corresponding GeF
4 is prepared analogously, except that the thermal "cracking" requires 700 °C. SiF
4 can also be created by placing silicon dioxide in hydrofluoric acid using the following equation:
Uses
This volatile compound finds limited use in microelectronics and organic synthesis.
Occurrence
Volcanic plumes contain significant amounts of silicon tetrafluoride. Production can reach several tonnes per day. The silicon tetrafluoride is partly hydrolysed and forms hexafluorosilicic acid.