title: 4,4,5,5-Tetra-methyl-2-(4-pyridinio)-2-imidazoline-1-oxyl-3-oxide perchlorate.
abstract: The crystal structure of the title compound, C(12)H(17)N(3)O(2) (+)·ClO(4) (-), consists of 4,4,5,5-tetra-methyl-2-(4-pyridinio)imidazoline-1-oxyl-3-oxide radical cations and perchlorate anions. Both the cation and the Cl atom of the anion are located on the same twofold rotation axis, and the crystal structure shows the average structure for the radical cation. The five-membered ring assumes a half-chair conformation. The cation links with the anion via N-H⋯O hydrogen bonding.
authors.affiliation: College of Chemistry and Environmental Science, Henan Normal University, Xinxiang 453002, People's Republic of China.
authors.forename: Zhi-Yong
authors.initials: ZY
authors.lastname: Gao
authors.forename: Jiu-Li
authors.initials: JL
authors.lastname: Chang
authors.forename: Dong
authors.initials: D
authors.lastname: Xian
authors.forename: Kai
authors.initials: K
authors.lastname: Jiang