The sp3 hybridization model also can be used for molecules involving N and 0, with lone electron pairs filling some of the sp3 orbitals. Thus an improved picture of water (below) employs two of the sp3 orbitals in bonds with hydrogen, and the other two for the two lone electron pairs on 0. This sp3 model predicts a tetrahedral H-0-H bond angle of 109.51. The smaller observed angle of 105 can be explained by the strong repulsion generated by the lone pairs, which are closer to the oxygen atom and to each other than are the bonding electron pairs.