title: Octahedral aromaticity in (2S+1)A1g X6(q) clusters (X = Li-C and Be-Si, S = 0-3, and q = -2 to +4).
abstract: It is generally observed that quintessential aromatic compounds have delocalised electronic configurations that are of closed-shells or open-shells half-filled with the same spin electrons. Guided by this property, we search for aromatic octahedral clusters of the type X6(q) (X = Li-C and Be-Si, q = -2 to +4) in (2S+1)A1g electronic states with spin multiplicities ranging from the singlet to the septet. With some exceptions, we find that closed-shells or open-shells half-filled with same spin electron systems have large multicentre indices and negative NICS values that are characteristic patterns of aromatic compounds. Our results confirm the existence of octahedral aromaticity but do not allow us to define a general rule for octahedral aromaticity because the ordering of molecular orbitals does not remain the same for different octahedral clusters.
authors.affiliation: Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Campus Montilivi, 17071 Girona, Spain. miquel.sola@udg.edu ferran.feixas@gmail.com.
authors.forename: Ouissam
authors.initials: O
authors.lastname: El Bakouri
authors.affiliation: Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Campus Montilivi, 17071 Girona, Spain. miquel.sola@udg.edu ferran.feixas@gmail.com.
authors.forename: Miquel
authors.initials: M
authors.lastname: Duran
authors.affiliation: Department of Theoretical Chemistry and Amsterdam Center for Multiscale Modeling, Vrije Universiteit Amsterdam, De Boeleaan 1083, NL-1081HV Amsterdam, The Netherlands and Institució Catalana de Recerca i Estudis Avançats (ICREA) and Departament de Química Orgànica, Universitat de Barcelona, Martí i Franquès 1-11, 08028 Barcelona, Catalonia, Spain.
authors.forename: Jordi
authors.initials: J
authors.lastname: Poater
authors.affiliation: Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Campus Montilivi, 17071 Girona, Spain. miquel.sola@udg.edu ferran.feixas@gmail.com.
authors.forename: Ferran
authors.initials: F
authors.lastname: Feixas
authors.affiliation: Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Campus Montilivi, 17071 Girona, Spain. miquel.sola@udg.edu ferran.feixas@gmail.com.
authors.forename: Miquel
authors.initials: M
authors.lastname: Solà