title: Li7(BH)5(+): a new thermodynamically favored star-shaped molecule.
abstract: The potential energy surfaces (PESs) of Lin(BH)5(n-6) systems (where n = 5, 6, and 7) were explored using the gradient embedded genetic algorithm (GEGA) program, in order to find their global minima conformations. This search predicts that the lowest-energy isomers of Li6(BH)5 and Li7(BH)5(+) contain a (BH)5(6-) pentagonal fragment, which is isoelectronic and structurally analogous to the prototypical aromatic hydrocarbon anion C5H5(-). Li7(BH)5(+), along with Li7C5(+), Li7Si5(+) and Li7Ge5(+), joins a select group of clusters that adopt a seven-peak star-shape geometry, which is favored by aromaticity in the central five-membered ring, and by the preference of Li atoms for bridging positions. The theoretical analysis of chemical bonding, based on magnetic criteria, supports the notion that electronic delocalization is an important stabilization factor in all these star-shaped clusters.
authors.affiliation: Doctorado en Fisicoquímica Molecular, Facultad de Ciencias Exactas, Universidad Andres Bello, República 275, Santiago, Chile.
authors.forename: Juan J
authors.initials: JJ
authors.lastname: Torres-Vega
authors.forename: Alejandro
authors.initials: A
authors.lastname: Vásquez-Espinal
authors.forename: Maria J
authors.initials: MJ
authors.lastname: Beltran
authors.forename: Lina
authors.initials: L
authors.lastname: Ruiz
authors.forename: Rafael
authors.initials: R
authors.lastname: Islas
authors.forename: William
authors.initials: W
authors.lastname: Tiznado
mesh_terms: D001895:Boron / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry*; D008094:Lithium / Q000737:chemistry*; D011789:Quantum Theory; D013816:Thermodynamics
chemical_list: D006859:Hydrogen; D008094:Lithium; D001895:Boron