Hybridization Calculator

Hybridization describes how atomic orbitals mix to form new orbitals for bonding. The key number is the steric number: the total count of electron domains around the central atom, which is the number of bonding partners plus the number of lone pairs.

Steric number 2: sp hybridization. Two hybrid orbitals form, pointing in opposite directions (180 degrees). The remaining two p orbitals are available for pi bonds. Examples: CO2, BeCl2, C in an alkyne.

Steric number 3: sp2 hybridization. Three hybrid orbitals in a plane, 120 degrees apart. One p orbital perpendicular to the plane. Examples: BF3, carbons in ethylene, nitrate ion.

Steric number 4: sp3. Four equivalent orbitals pointing toward the corners of a tetrahedron (109.5 degrees). This is the most common for carbon in organic chemistry, and for nitrogen, oxygen, and sulfur with lone pairs. Water is sp3 with two bonding and two lone pairs.

Steric number 5: sp3d. Trigonal bipyramidal electron geometry. Requires d-orbital participation, so only possible for elements in period 3 and beyond (P, S, Cl, etc.). PCl5 is the textbook example.

Steric number 6: sp3d2. Octahedral electron geometry. SF6 is the classic case. All six domains point toward the vertices of an octahedron.

One thing to keep in mind: multiple bonds (double or triple) count as a single bonding domain for the purposes of hybridization, even though they contain more electron density than a single bond. The pi electrons in a double bond occupy unhybridized p orbitals, not the hybrid orbitals.

Steric numbers above 6 are theoretically possible for very large atoms but are rarely stable at room temperature and are not covered here.