Charged nano-colloidal particles self-assemble and display ordered arrays or other structures at liquid interfaces. We used Monte Carlo (MC) simulations to examine the effect of long-range repulsive collective inter-particle interactions on structural transitions from liquid-like to crystallike. We used the asymptotic pair interaction potential proposed by Hurd (I. Phys. A. Math Gen 18, L1055 (1985)), which includes both the screened Coulombic contribution and the dipole-dipole interaction. The effects of the collective inter-particle interactions on the interfacial 2-D colloid structure formation were quantified by the radial distribution function and the potential of the mean force. The MC simulations agreed with the experimentally observed particle structural transitions at both the air-water and oil-water interfaces. The effects of the particle charge and interfacial coverage on the 2-D structure formation were analyzed. The significance of the results lies in their potential applications in inducing 2-D structural transitions in interfacial colloids to form ordered structures; this controls the emulsion and foam stability, and aids in the fabrication of patterned materials with desirable properties.