title: Effect of high pressure on the typical supramolecular structure of guanidinium methanesulfonate.
abstract: We report the high-pressure response of guanidinium methanesulfonate (C(NH(2))(3)(+)·CH(3)SO(3)(-), GMS) using in situ Raman spectroscopy and synchrotron X-ray diffraction (XRD) techniques up to the pressures of ~11 GPa. GMS exhibits the representative supramolecular structure of two-dimensional (2D) hydrogen-bonded bilayered motifs under ambient conditions. On the basis of the experimental results, two phase transitions were identified at 0.6 and 1.5 GPa, respectively. The first phase transition, which shows the reconstructive feature, is ascribed to the rearrangements of hydrogen-bonded networks, resulting in the symmetry transformation from C2/m to Pnma. The second one proves to be associated with local distortions of methyl groups, accompanied by the symmetry transformation from Pnma to Pna2(1). The cooperativity of hydrogen bonding, electrostatic, and van der Waals interactions, as well as mechanisms for the phase transitions is discussed by means of the local nature of the structure.
authors.affiliation: State Key Laboratory of Superhard Materials, Jilin University, Changchun 130012, China.
authors.forename: Shourui
authors.initials: S
authors.lastname: Li
authors.forename: Qian
authors.initials: Q
authors.lastname: Li
authors.forename: Jing
authors.initials: J
authors.lastname: Zhou
authors.forename: Run
authors.initials: R
authors.lastname: Wang
authors.forename: Zhangmei
authors.initials: Z
authors.lastname: Jiang
authors.forename: Kai
authors.initials: K
authors.lastname: Wang
authors.forename: Dapeng
authors.initials: D
authors.lastname: Xu
authors.forename: Jing
authors.initials: J
authors.lastname: Liu
authors.forename: Bingbing
authors.initials: B
authors.lastname: Liu
authors.forename: Guangtian
authors.initials: G
authors.lastname: Zou
authors.forename: Bo
authors.initials: B
authors.lastname: Zou