title: A chemically triggered and thermally switched dielectric constant transition in a metal cyanide based crystal.
abstract: A dielectric constant transition is chemically triggered and thermally switched in (HPy)2[Na(H2O)Co(CN)6] (2, HPy=pyridinium cation) by single-crystal-to-single-crystal transformation and structural phase transition, respectively. Upon dehydration, (HPy)2[Na(H2O)2Co(CN)6] (1) transforms to its semi-hydrated form 2, accompanying a transition from a low-dielectric state to a high-dielectric state, and vice versa. This dielectric switch is also realized by a structural phase transition in 2 that occurs between room- and low-temperature phases, and which corresponds to high- and low-dielectric states, respectively. The switching property is due to the variation in the environment surrounding the HPy cation, that is, the hydrogen-bonding interactions and the crystal packing, which exert predominant influences on the dynamics of the cations that transit between the static and motional states.
authors.affiliation: Ordered Matter Science Research Center, Southeast University, Nanjing 211189, Jiangsu (China).
authors.forename: Chao
authors.initials: C
authors.lastname: Shi
authors.affiliation: Department of Physics & Shanghai Key Laboratory of Magnetic Resonance, East China Normal University, North Zhongshan Road 3663, Shanghai 200062 (China).
authors.forename: Xi
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Ordered Matter Science Research Center, Southeast University, Nanjing 211189, Jiangsu (China).
authors.forename: Ying
authors.initials: Y
authors.lastname: Cai
authors.affiliation: Department of Physics & Shanghai Key Laboratory of Magnetic Resonance, East China Normal University, North Zhongshan Road 3663, Shanghai 200062 (China). yfyao@phy.ecnu.edu.cn.
authors.forename: Ye-Feng
authors.initials: YF
authors.lastname: Yao
authors.affiliation: Ordered Matter Science Research Center, Southeast University, Nanjing 211189, Jiangsu (China). zhangwen@seu.edu.cn.
authors.forename: Wen
authors.initials: W
authors.lastname: Zhang
keywords: cyanide; phase transitions; pyridinium; single-crystal-to-single-crystal transformations; switchable dielectric constant