Interactions of a Mn atom with halogen atoms and stability of its half-filled 3d-shell

Abstract

Using density functional theory with hybrid exchange-correlation potential, we have calculated the geometrical and electronic structure, relative stability, and electron affinities of MnX ncompounds (n = 1–6) formed by a Mn atom and halogen atoms X = F, Cl, and Br. Our objective is to examine the extent to which the Mn–X interactions are similar and to elucidate if/how the half-filled 3d-shell of a Mn atom participates in chemical bonding as the number of halogen atoms increases. While the highest oxidation number of the Mn atom in fluorides is considered to be +4, the maximum number of halogen atoms that can be chemically attached in the MnX n −anions is 6 for X = F, 5 for X = Cl, and 4 for X = Br. The MnCl n and MnBr n neutrals are superhalogens for n ≥ 3, while the superhalogen behavior of MnF n begins with n = 4. These results are explained to be due to the way different halogen atoms interact with the 3d electrons of Mn atom