title: Technetium(IV) halides predicted from first-principles.
abstract: We report the crystal structures of the novel technetium tetrahalides TcX(4) [X = F, I], as predicted from first-principles calculations. Isomorphous with TcCl(4) and TcBr(4) crystals, TcF(4) is orthorhombic with the centro-symmetric space group Pbca, while TcI(4) crystallizes in the monoclinic space group P2(1)/c. The structures, [TcX(2)(mu-X)(4/2)](infinity), consist of distorted edge-sharing octahedral groups of composition TcX(6) linked into endless cis chains. A possible explanation for the differences between these structures is offered in terms of varying degrees of bonding within the chains.
authors.affiliation: Department of Chemistry and Harry Reid Center for Environmental Studies, University of Nevada Las Vegas, 4505 Maryland Parkway, Las Vegas, Nevada 89154, USA. weckp@unlv.nevada.edu
authors.forename: Philippe F
authors.initials: PF
authors.lastname: Weck
authors.forename: Eunja
authors.initials: E
authors.lastname: Kim
authors.forename: Frédéric
authors.initials: F
authors.lastname: Poineau
authors.forename: Efrain E
authors.initials: EE
authors.lastname: Rodriguez
authors.forename: Alfred P
authors.initials: AP
authors.lastname: Sattelberger
authors.forename: Kenneth R
authors.initials: KR
authors.lastname: Czerwinski