title: Compression icing of room-temperature NaX solutions (X = F, Cl, Br, I).
abstract: In situ Raman spectroscopy revealed that transiting H2O/NaX (∼64) solutions into an ice VI phase and then into an ice VII phase at a temperature of 298 K requires excessive pressures with respect to pure water. The increase of the critical pressures varies with the solute type in the Hofmeister series order: X = I > Br > Cl > F ∼ 0. The results suggest that the solute hydration creates electric fields that lengthen and soften the O:H nonbond and meanwhile shorten and stiffen the H-O bond through O-O Coulomb repulsion. Compression, however, does the opposite to solute electrification upon the O:H-O bond relaxation. Therefore, compression of the aqueous solutions recovers the electrification-deformed O:H-O bond first and then proceeds to the phase transitions, which requires excessive energy for the same sequence of phase transitions. Ice exclusion of solute disperses the frequencies of characteristic phonons and the critical pressures with unlikely new bond formation.
authors.affiliation: State Key Laboratory of Superhard Materials, Jilin University, Changchun 130012, China. zoubo@jlu.edu.cn.
authors.forename: Qingxin
authors.initials: Q
authors.lastname: Zeng
authors.affiliation: State Key Laboratory of Superhard Materials, Jilin University, Changchun 130012, China. zoubo@jlu.edu.cn.
authors.forename: Tingting
authors.initials: T
authors.lastname: Yan
authors.affiliation: State Key Laboratory of Superhard Materials, Jilin University, Changchun 130012, China. zoubo@jlu.edu.cn.
authors.forename: Kai
authors.initials: K
authors.lastname: Wang
authors.affiliation: Institute of Coordination Bond Metrology and Engineering, College of Materials Science and Engineering, China Jiliang University, Hangzhou 310018, China.
authors.forename: Yinyan
authors.initials: Y
authors.lastname: Gong
authors.affiliation: Key Laboratory of Low-Dimensional Materials and Application Technologies (Ministry of Education) and School of Materials Science and Engineering, Xiangtan University, Hunan 411105, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: Key Laboratory of Low-Dimensional Materials and Application Technologies (Ministry of Education) and School of Materials Science and Engineering, Xiangtan University, Hunan 411105, China.
authors.forename: Yongli
authors.initials: Y
authors.lastname: Huang
authors.affiliation: NOVITAS, School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798, Singapore. ecqsun@ntu.edu.sg.
authors.forename: Chang Q
authors.initials: CQ
authors.lastname: Sun
authors.affiliation: State Key Laboratory of Superhard Materials, Jilin University, Changchun 130012, China. zoubo@jlu.edu.cn.
authors.forename: Bo
authors.initials: B
authors.lastname: Zou