title: Diaqua-(1,4,8,11-tetra-aza-cyclo-tetra-deca-ne)nickel(II) fumarate tetra-hydrate.
abstract: The asymmetric unit of the title complex salt, [Ni(C(10)H(24)N(4))(H(2)O)(2)](C(4)H(2)O(4))·4H(2)O, comprises half of a nickel(II) complex dication, half of a fumarate dianion and two water mol-ecules. Both the Ni(II) cation and fumarate anion lie on a crystallographic inversion center. The Ni(II) ion in the cyclam complex is six-coordinated within a distorted N(4)O(2) octa-hedral geometry, with the four cyclam N atoms in the equatorial plane and the two water mol-ecules in apical positions. The six-membered metalla ring adopts a chair conformation, whereas the five-membered ring exists in a twisted form. In the crystal packing, inter-molecular O-H⋯O hydrogen bonds between the water molecules and the carboxyl groups of the fumarate anions lead to the formation of layers with R(4) (2)(8) ring motifs. Ni(II) complex cations are sandwiched between two such layers, being held in place by O-H⋯O, N-H⋯O and C-H⋯O hydrogen bonds, consolidating a three-dimensional network.
authors.forename: Shao Liang
authors.initials: SL
authors.lastname: Lim
authors.forename: Chew Hee
authors.initials: CH
authors.lastname: Ng
authors.forename: Siang Guan
authors.initials: SG
authors.lastname: Teoh
authors.forename: Wan-Sin
authors.initials: WS
authors.lastname: Loh
authors.forename: Hoong-Kun
authors.initials: HK
authors.lastname: Fun