Elements in group fourteen are mostly known to form compounds in which there are four electron domains leading to a tetrahedral electron domain geometry.
However, the presence of lone pairs affects the shape of the molecule. SnCl3− has four electron domains, three of them are bond pairs while one is a lone pair. The shape of the molecule is based on a tetrahedron, however the observed geometry is trigonal pyramidal due to the presence of the lone pair. Its bond angle is now less than the predicted 109 degrees.
