title: 4,7,13,18-Tetra-oxa-1,10-diazo-nia-bicyclo-[8.5.5]icosane bis-(hexa-fluorido-phosphate).
abstract: The asymmetric unit of the title structure, C(14)H(30)N(2)O(4) (2+)·2PF(6) (-), contains the anion and half of the cation, the latter being completed by a crystallographic twofold axis. The cation has a cage structure with the ammonium H atoms pointing into the cage. These H atoms are shielded from inter-molecular inter-actions and form only intra-molecular contacts. There are short inter-molecular C-H⋯F inter-actions in the structure, but no conventional inter-molecular hydrogen bonds.
authors.forename: Nalinava
authors.initials: N
authors.lastname: Sen Gupta
authors.forename: David S
authors.initials: DS
authors.lastname: Wragg
authors.forename: Mats
authors.initials: M
authors.lastname: Tilset
authors.forename: Jon Petter
authors.initials: JP
authors.lastname: Omtvedt
references.citation: Acta Crystallogr A. 2008 Jan;64(Pt 1):112-22
references.pmid: 18156677
references.citation: Angew Chem Int Ed Engl. 2009;48(34):6332-4
references.pmid: 19618404
references.citation: Acta Crystallogr Sect E Struct Rep Online. 2011 Aug 1;67(Pt 8):o1929-30
references.pmid: 22090974