Editing VSEPR theory (section)

===Steric number===
[[Image:Sulfur-tetrafluoride-2D-dimensions.png|thumb|Sulfur tetrafluoride has a steric number of 5.]]
The steric number of a central atom in a molecule is the number of atoms bonded to that central atom, called its [[coordination number]], plus the number of [[lone pair]]s of valence electrons on the central atom.<ref>{{cite book|first1=G. L. |last1=Miessler |first2=D. A. |last2=Tarr |title=Inorganic Chemistry |edition=2nd |publisher=Prentice-Hall |year=1999 |pages=55 |isbn=978-0-13-841891-5}}</ref> In the molecule [[Sulfur tetrafluoride|SF<sub>4</sub>]], for example, the central sulfur atom has four [[ligand]]s; the [[coordination number]] of sulfur is four. In addition to the four ligands, sulfur also has one lone pair in this molecule. Thus, the steric number is 4 + 1 = 5.