title: CBe5E- (E = Al, Ga, In, Tl): planar pentacoordinate carbon in heptaatomic clusters.
abstract: A series of clusters with the general formula CBe(5)E(-) (E = Al, Ga, In, Tl) are theoretically shown to have a planar pentacoordinate carbon atom. The structures show a simple and rigid topological framework-a planar EBe(4) ring surrounding a C center, with one of the ring Be-Be bonds capped in-plane by a fifth Be atom. The system is stabilized by a network of multicenter σ bonds in which the central C atom is the acceptor, and π systems as well by which the C atom donates charge to the Be and E atoms that encircle it.
authors.affiliation: Universidad de Guanajuato, Noria Alta s/n, Guanajuato, Guanajuato C.P. 36050, Mexico.
authors.forename: Abril C
authors.initials: AC
authors.lastname: Castro
authors.forename: Gerardo
authors.initials: G
authors.lastname: Martínez-Guajardo
authors.forename: Thomas
authors.initials: T
authors.lastname: Johnson
authors.forename: Jesus M
authors.initials: JM
authors.lastname: Ugalde
authors.forename: Yan-bo
authors.initials: YB
authors.lastname: Wu
authors.forename: José M
authors.initials: JM
authors.lastname: Mercero
authors.forename: Thomas
authors.initials: T
authors.lastname: Heine
authors.forename: Kelling J
authors.initials: KJ
authors.lastname: Donald
authors.forename: Gabriel
authors.initials: G
authors.lastname: Merino