# Why does SiF4 act as a lewis acid?

Jan 4, 2016

${\text{SiF}}_{4}$ can act as a Lewis acid because $\text{Si}$ can expand its octet.

#### Explanation:

A Lewis acid is an electron-pair acceptor.

(from chemwiki.ucdavis.edu)

${\text{SiF}}_{4}$ can accept electron pairs and expand its octet to 12.

For example, it reacts with ${\text{F}}^{-}$ to form ${\text{SiF}}_{6}^{2 -}$ [hexafluoridosilicate(2-)]