NH_(4)Cl的高压相变及弹性性质实验研究  

Phase Transitions and Elastic Properties of NH_(4)Cl at High Pressures

作　　者：张静宜 黄圣轩[1,2] 秦善 ZHANG Jingyi;HUANG Shengxuan;QIN Shan(The Key Laboratory of Orogenic Belts and Crustal Evolution(MOE),School of Earth and Space Sciences,Peking University,Beijing 100871;Geodynamics Research Center,Ehime University,Ehime 790-8577)

机构地区：[1]造山带与地壳演化教育部重点实验室,北京大学地球与空间科学学院,北京100871 [2]Geodynamics Research Center,Ehime University,Ehime 790-8577

出　　处：《北京大学学报(自然科学版)》2025年第1期121-129,共9页Acta Scientiarum Naturalium Universitatis Pekinensis

基　　金：国家自然科学基金(42072047)资助。

摘　　要：在高压环境下,对天然卤砂(NH_(4)Cl)进行同步辐射单晶X射线衍射(XRD)、拉曼光谱和红外光谱分析。结果表明,NH_(4)Cl在13.6 GPa发生相变,从Ⅳ相(空间群为P43Pm)变为Ⅴ相(空间群为P4/nmm);Ⅳ相和Ⅴ相NH_(4)Cl的三阶Birch-Murnaghan状态方程参数分别为K0=24.9(1)GPa,V0=56.4(1)Å^(3),K0′=5.5以及K0=35(25)GPa,V0=110(11)Å^(3),K0′=3.8(13)。NH_(4)Cl的拉曼光谱在13.7 GPa出现新峰和不连续变化,其拉曼位移与压强呈现线性关系,据此获得Ⅳ相和Ⅴ相NH_(4)Cl各拉曼振动的位移量随压强的变化,并计算格林乃森参数。NH_(4)Cl的红外光谱在11.7~14.8 GPa出现N-H振动峰分裂。NH_(4)Cl,NH_(4)Br和NH_(4)I的Ⅳ-Ⅴ相变压强依次降低,表现出与阴离子半径成反比的规律。Synchrotron radiation single crystal X-ray diffraction(XRD),Raman spectroscopy and infrared spectro-scopy were used to analyze natural ammonium chloride(NH_(4)Cl)under high pressure.The results show that NH_(4)Cl transforms from phaseⅣ(space group P43m)to phaseⅤ(space group P4/nmm)at 13.6 GPa.The parameters of the third-order Birch-Murnaghan equation of state are determined with K0=24.9(1)GPa,V0=56.4(1)Å^(3),K0′=5.5 for phaseⅣ,and K0=35(25)GPa,V0=110(11)Å^(3),K0′=3.8(13)for phase V.The Raman spectrum of NH_(4)Cl shows new peaks and discontinuity at 13.7 GPa,and the Raman shift are linearly related to pressure.dν_(i)/dP and Grüneissen parameters for each vibration of phaseⅣandⅤare obtained.The infrared spectrum of N-H vibration split at 11.7-14.8 GPa.The transition pressures from phaseⅣtoⅤof NH_(4)Cl,NH_(4)Br and NH_(4)I decrease in turn,which are inver-sely proportional to the anion radius.

关 键 词：氯化铵 高压结构相变 X射线衍射 拉曼光谱 红外光谱 

分 类 号：TQ113.72[化学工程—无机化工] P595[天文地球—地球化学]