Electride Characteristics of M2(h5-E5)2 (M= Be, Mg; E= Sb5-)

Ab initio computation is performed on the binuclear sandwich complexes, M2(η5-Sb5)2. Eclipsed and staggered conformations are generated due to the η5 mode of binding by Sb5- ligand with the alkaline earth metals (Be and Mg metals). The complexes are thermodynamically stable at room temperature. The electron density descriptors and the natural bond orbital (NBO) analysis confirmed the covalent nature of the M-M bond. Both Be2(η5-Sb5)2 and Mg2(η5-Sb5)2 complexes have one non-nuclear attractor (NNA) at the center of the M-M bond which is predicted and confirmed by the electron density analysis. At the NNA, the values of the Laplacian of electron density are negative and an electron localization function basin (ELF) is present at the center of the M-M bond for localized electrons. Both the complexes show large values of nonlinear optical (NLO) properties. Both the designed binuclear sandwich complexes Be2(η5-Sb5)2 and Mg2(η5-Sb5)2 behave as electride.