The coefficient of thermal expansion of the Si-O bond has been obtained from neutron total scattering measurements of five different phases of silica, with value (2.2±0.4)×10^-6 K^-1. This value is smaller than values obtained by conventional x-ray diffraction measurements corrected for rigid-body thermal motion. Three of the datasets used in this study, tridymite and two zeolite structures, are completely new.