The criteria to distinguish the structure of halogen adducts of aryl chalcogenides in solutions based on the NMR chemical shifts are confirmed by ab initio molecular orbitals (MO) calculations based on the gauge-including atomic orbitals (GIAO) theory. The criteria are applied to determine the structure of halogen adducts of 1, 2-bis (phenylselanyl) benzene (1), 1, 4-bis (phenylselanyl) benzene (2), and 1, 4-bis (p-tert-butylphenylselanyl) benzene ...