Related Experiment Video
Updated: Oct 11, 2025

From Molecules to Materials: Engineering New Ionic Liquid Crystals Through Halogen Bonding
Published on: March 24, 2018
Halogen-Ion-Induced Structural Phase Transition Giving a Polymorph of HgBr2 with Balanced Nonlinear Optical
1Hubei Key Laboratory of Pollutant Analysis & Reuse Technology, College of Chemistry and Chemical Engineering, Hubei Normal University, Huangshi 435002, People's Republic of China.
Abstract:
The key to developing new infrared nonlinear optical (NLO) materials is balancing second-order nonlinear optical effects and the laser-induced damage threshold (LIDT). In this paper, a new polymorph of HgBr2 (P212121) was synthesized by a "halogen-ion-induced effect" in solution, which features a crystal structure different from that of the original phase (Cmc21) and exhibits better NLO properties. Its powders show a strong SHG effect (9 × KDP), a high LIDT (30 × AgGaS2), a wide infrared transparent range, and stability in air, making it a prospective NLO material in the IR region. In addition, the above excellent NLO characteristics are well illustrated in DFT theoretical calculations. More importantly, experimental results show that the new infrared NLO polymorph with excellent comprehensive properties could be controllably obtained by using the halogen-ion-induced strategy.
More Related Videos
Related Concept Videos
Halogenation of Alkenes
Consider the bromination of cyclopentene. Molecular bromine is polarized in the proximity of the π electrons of cyclopentene. An electrophilic bromine atom adds across the double bond, forming a cyclic bromonium ion intermediate.
Formation of Halohydrin from Alkenes
Hybridization of Atomic Orbitals I
Electrophilic 1,2- and 1,4-Addition of HX to 1,3-Butadiene
Regioselectivity of Electrophilic Additions to Alkenes: Markovnikov's Rule
The hydrohalogenation of an unsymmetrical alkene can yield two haloalkane products, depending on which vinylic carbon takes up the halogen. However, one product usually predominates, where hydrogen adds to the vinylic carbon bearing the...
Phase Transitions: Sublimation and Deposition

