A zero-free interval for chromatic polynomials

Abstract It is proved that, for a wide class of near-triangulations of the plane, the chromatic polynomial has no zeros between 2 and 2.5. Together with a previously known result, this shows that the zero of the chromatic polynomial of the octahedron at 2.546602 ··· is the smallest non-integer real zero of any chromatic polynomial of a plane triangulation.