We propose a high-resolution neutron powder diffraction study of the complexes 1, 4-dioxane X2, where X = Cl, Br, I. These are the simplest halogen-bonded complexes in which a dihalogen acts as a bridging unit. These complexes have short O...X-X...O contacts, with each halogen atom bonding to an oxygen atom from a different dioxane molecule, thus producing an infinite chain motif. Theoretical work on related systems predicted the occurrence of complementary weak C-H¿X interactions oriented at right angles to the X-X molecule, which we have found in the acetone-Br2 complex. Our objectives here are: (1) to determine accurate metrical parameters for the complex; (2) to obtain thermal expansion coefficients, and (3) to investigate potential C-H...X interactions in these complexes. This is of relevance because of the role that halogen bonds can play in biological and chemical systems.