Unit cell is 5.43 Angstroms, according to this site: http://hyperphysics.phy-astr.gsu.edu/hbase/solids/sili2.html http://hyperphysics.phy-astr.gsu.edu/hbase/sol

Unit cell is 5.43 Angstroms, according to this site: http://hyperphysics.phy-astr.gsu.edu/hbase/solids/sili2.html http://hyperphysics.phy-astr.gsu.edu/hbase/solids/sili2.html. Of course the bonds by which the cell is constructed are smaller.