A theoretical study of the (ClC3H2)(+) species has been carried out. Two different models, the complete MP4 at MP2 geometries and the QCISD(T) at B3LYP geometries, have been employed. Our calculations predict that the global minimum is a cyclic isomer with a three-membered carbon ring, ClC3H2+((1)A(1)), whereas two different open-chain structures, ClCCCH2+((1)A(1)) and ClHCCCH+((1)A'), lie similar to 19 and 15 kcal/mol, respectively, higher in energy. The lowest-lying triplet state is an open-chain structure, ClCCCH2+((3)A "), which lies >57 kcal/mol above the global minimum. These theoretical results allow the development of thermodynamic arguments about the reaction pathways of the process Cl+ +- C3H2 For the reaction of Cl+ with vinylidenecarbene (1-C3H2), the production of ClCCCH+ is both thermodynamically and kinetically favored, and even the formation of ClC3H+ is also more exothermic than the charge transfer. In the reaction of Cl+ with cyclopropenylidene (c-C3H2), the production of both cyclic and open-chain chlorine-carbon compounds seems to be severely hindered; hence, charge transfer should be the dominant process. Consequently, only the reaction of Cl+ with 1-C3H2 seems to be a possible source of chlorine-carbon compounds in space, and the preferred product should be linear ClCCCH+, which could be a precursor to ClCCC.