Chem. J. Chinese Universities ›› 2018, Vol. 39 ›› Issue (12): 2700.doi: 10.7503/cjcu20180481

• Physical Chemistry • Previous Articles     Next Articles

Synthesis of Urea Ammonium Halide Cocrystal and Theoretical Study of Its Influencing Factors in Water System

YAN Xuan, XUE Bingchun*(), LIU Erbao*()   

  1. School of Chemistry and Materials Science, Shanxi Normal University, Linfen 041001, China
  • Received:2018-07-05 Online:2018-12-03 Published:2018-11-05
  • Contact: XUE Bingchun,LIU Erbao E-mail:bcxue@sxnu.edu.cn;liueb@sxnu.edu.cn
  • Supported by:
    † Supported by the Natural Science Foundation of Shanxi Province, China(No.2012011009-3).

Abstract:

Three urea ammonium halide cocrystals were synthesized by slow evaporation technique. It was found that the urea ammonium chloride was still easy to synthesize than the other two urea ammonium halide. The first-principles method was used to construct isomorphous urea ammonium fluoride and urea ammonium bromide cocrystal unit cell based on the original unit structure of urea ammonium chloride. The stability, packing coefficient, formation energy of the three urea ammonium halide cocrystal structures, halogen ion radius and electronegativity, and ionic hydration energy were compared. The results showed that for the urea ammonium bromide cocrystal, the larger Br- radius leads to the deformation of the internal cavity of the urea cell, and the hydrated cluster of bromide ions is stable, which will hinder the entry of Br- into the urea channel; for urea ammonium fluoride cocrystal, the electronegativity of F-makes the fluoride ion hydrate cluster F-(H2O)5 very stable, preventing the bare F- entering the urea cavity; for the urea ammonium chloride cocrystal, the electronegativity and radius size of Cl- are both moderate, the stability of hydrated ion clusters is appropriate, all these factors make it easy to enter the urea cavity.

Key words: Urea cocrystal, Ammonium halide, Influence factor, Theoretical calculation

CLC Number: 

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