A previous study of the binary system, [Sb 2 O 3 ] x -[ZnCl 2 ] 1−x (Johnson et al 2003 J. Phys.: Condens. Matter 15 755-64), where nominally x = 0.25, 0.50, 0.75 and 1.00, has been extended to include Sb 2 O 3 -PbCl 2 . Information about the structure has been obtained from a combination of neutron and x-ray diffraction measurements, which were complemented by x-ray photoelectron spectroscopy. The data clearly show preferential bonding of oxygen to antimony and chlorine to zinc or lead in a single-phase glass with minimal change in the polyhedral structure with composition. The structure appears to be controlled by the need to avoid Sb-Cl-Sb links.