In an #sp^3# hybridization, #color(red)"one"# #s# orbital is mixed with #color(red)"three"# #p# orbitals to form #color(red)"four"# #sp^3# hybridized orbitals. Each of these hybridized orbitals have 25% s character and 75% p character (calculated according to the proportion of s:p mixing). These #sp^3# hybridized orbitals are oriented with bond angle of 109.5 degrees to minimize electron repulsion, in a tetrahedral geometry. An example of #sp^3# hybridization can be seen in the carbons in ethane.
In an #sp^2# hybridization, #color(red)"one"# #s# orbital is mixed with #color(red)"two"# #p# orbitals to form #color(red)"three"# #sp^2# hybridized orbitals. Each of these hybridized orbitals have 33% s character and 67% p character. These #sp^2# hybridized orbitals are oriented with bond angle of 120 degrees, in a trigonal planar (triangular) geometry. The remaining p orbital is unchanged and perpendicular to the plane of the hybridized orbitals. An example of #sp^2# hybridization can be seen in the carbons in ethene.
In an #sp# hybridization, #color(red)"one"# #s# orbital is mixed with #color(red)"one"# #p# orbitals to form #color(red)"two"# #sp# hybridized orbitals. Each of these hybridized orbitals have 50% s character and 50% p character. These #sp# hybridized orbitals are oriented with bond angle of 180 degrees, in a linear geometry. The remaining two p orbitals are unchanged, and perpendicular to each other and the plane of the hybridized orbitals. An example of #sp# hybridization can be seen in the carbons in ethyne.
The mixing of orbitals can be seen here:
Orientation of the hybridized orbitals in respective geometries:
