FIGURE 4.8 When electrons with
opposite spins (depicted as c and T) in
two hydrogen 1s-orbitals pair and the
s-orbitals overlap, they form a -bond,
which is depicted here by the boundary
surface of the electron cloud. The cloud
has cylindrical symmetry around the
internuclear axis and spreads over both
nuclei. In the illustrations in this book,
-bonds are usually colored blue.