The dependence of the electronic and magnetic properties on the atomic arrangements of three different phases (i.e. alpha, beta, and gamma phases), of the half-Heusler alloy PdMnBi, is investigated based on spin-polarized density functional theory. For each phase, the optimized lattice constant is determined and the possibility of finding a half-metal is explored. Throughout this study, the bonding features of each phase are not supported by the large electronegativity of Pd given in the public domain. Both alpha and beta phases PdMnBi show half-metallic (HM) properties for a range of lattice constants, and their magnetic moments are consistent with the values given by the modified Slater-Pauling rule. Additionally, the effects of the spin-orbit (S-O) interaction are examined by comparing the relative shifts of the valence bands and the indirect semiconducting gap, with respect to the spin-polarized results. (C) 2014 Elsevier B.V. All rights reserved.