We use density functional theory (DFT) to predict the chemical reactivity of CS molecule on third-row maingroup dicarbides, C2X (X = K-Br). An analysis of the frontier molecular orbitals (FMOs) of bare C2X clusters suggests that carbon atoms of C2X clusters is the most active site for CS interaction. Using Bader's approach, the nature of interactions between CS molecule and the host C2X clusters has been studied by examining computational parameters at the bond critical points (BCPs) of the clusters. It is noted that, in all the clusters, rho(CC2X-CCS) > 0.30 a.u. with negative del(2) rho(C-C) at BCPs of carbon atoms of both C2X and CS, indicating a shared-electron interaction between C2X and CS. (C) 2017 Elsevier B.V. All rights reserved.