sp Hybrids. The top two images show the two sp hybrids at a slight angle. These particular sp hybrids are combinations of 2s and 2p functions. The bottom shows the relative positions of these two hybrids superimposed. Note that in each case, the nucleus is embedded in the minor lobe.
There are two sp hybrid orbitals. Each is the same as the other but one is rotated by 180° relative to the other. It is appropriate to invoke sp hybrid orbitals in molecules such as BeH2 or HCCH (ethyne) where the H-Be-H and H-C-C angles are 180°.