title: Bis[5-(pyridin-2-yl)pyrazine-2-carbo-nitrile-κ(2)N(4),N(5)](trifluoro-acetato-κO)silver(I).
abstract: In the asymmetric unit of the title compound, [Ag(C(10)H(6)N(4))(2)(CF(3)CO(2))], there two mononuclear but slightly different complex units. In each, two κ(2)N:N-chelating 5-(pyridin-2-yl)pyrazine-2-carbonitrile ligands surround the Ag(I) atom, giving an N(4)O square-pyramidal coordination geometry with one trifluoro-acetate O atom at the apex. The difference between the two lies in the Ag-N bond lengths: in one complex, three normal [range 2.272 (5)-2.552 (5) Å] and one long [2.706 (4) Å] and in the second, two normal [2.254 (5) and 2.290 (5) Å] and two long [2.647 (5) and 2.675 (5) Å] are present. Short inter-molecular F⋯F contacts [2.586 (4) Å] and weak π-π stacking inter-actions [minimum ring centroid separation 3.836 (5) Å] between pyridyl and pyrazinyl rings connect the complex units, forming columns which extend along the b-axis direction.
authors.affiliation: Tianjin Entry-Exit Inspection and Quarantine Bureau, Tianjin 300201,  People's Republic of China.
authors.forename: Jing
authors.initials: J
authors.lastname: Li
authors.forename: Xiao Cuan
authors.initials: XC
authors.lastname: Jia
authors.forename: Jun
authors.initials: J
authors.lastname: Qi
authors.forename: Yuan Yuan
authors.initials: YY
authors.lastname: Liu
authors.forename: Yu
authors.initials: Y
authors.lastname: Ding