In a simple tight-binding picture, the band width is furthermore linearly related to the coordination of the atom. Hence, a higher coordination also increases the band width, which results in a weaker bond between this surface atom and an adsorbed species. Correspondingly, lower coordination as experienced for step and kink atoms (undercoordinated sites) leads to stronger adsorption bonds. This effect, which corresponds closely to the principle of constant bond order (see discussion below), was demonstrated both experimentally ad theoretically. Experimentally, such a trend was reported, e.g.,