In the following model, the sp2 carbon atom is dark gray, oxygen is red and the hydrogens are cyan. The 1s orbitals of carbon and oxygen are not part of the molecular orbitals shown here. The remaining atomic orbitals generate ten molecular orbitals, six of which (colored green) are occupied by twelve electrons in pairs. These orbitals and their energies in electron volts are shown in the diagram on the right of the model. By clicking on the orbital name, each orbital will be displayed on the model . The different phases of the molecular orbitals are colored red and blue and are separated by nodal surfaces at which electron density is zero. A Lewis formula consists of two C–H sigma bonds, a C–O sigmabond, a C=O pi bond and two non-bonding electron pairs. Because of overlap mixing, the molecular orbitals are not as localized as the Lewis structure suggests. The lowest energy M.O (#1) is essentially the C–O sigma bond. The next two orbitals (#2 & 3) are primarily the C–H sigma bonds. Orbital #4 is occupied by one of the non-bonding pairs, chiefly in an sp hybrid region on oxygen. Orbital #5 is the π-bonding orbital, leaving orbital #6 for the remaining non-bonding pair. Unlike #4, this electron pair occupies an oxygen p-orbital. Antibonding orbital #7 is clearly the π* orbital. The molecules and their orbitals may be rotated by clicking on the structure and dragging the mouse. Holding the shift key during this operation allows zooming.