The temperature-dependent,second-order,nonlinear,optical coefficient（x^（（2）））.piezoelectric coefficient （d_（33））,pyroelectric coefficient（Ps） and domains on triglycine sulfate（TGS） reported herein provide a clue for us to investigate these as a typical second-order phase transition.The symmetry breaking occurrence is definitely confirmed by the temperature-dependent x^（（2）） in which x^（（2）） displays a limited value at the ferroelectric phase,indicating the space group（P2_1） chosen is correct,and when x^（（2）） basically maintains a zero value at the paraelectric phase,indicating the space group should be centric.Interestingly,after normalization of x^（（2））,d_（33） or Ps,the change trend with temperature is basically overlapped,probably abiding by Landau theory.Moreover,temperature-dependent domains directly show the symmetry breaking occurrence.
A clean and saIe synthesis method of 5-（4＇-methylbiphenyl-2-yl）-1H-tetrazole was round： under hydrothermal conditions, 1.2 equiv, of 4＇-methylbiphenyl-2-carbonitrile react with 1 equiv, of sodium azide in a mixed solvent of propane-1,2-diol/H2O, with 1.5 equiv, of ammonium chloride and 0.2 equiv. of ammonium fluoride as catalyst. After simple post-processing, the yield can be improved to 95%, and the purity of the product is 99% without further recrystaUization.
