马鞍山绿松石中水的振动光谱表征及其意义

STUDY ON THE VIBRATIONAL SPECTRA CHARACTERS OF WATER IN TURQUOISE FROM MA′ANSHAN

在室温和变温条件下对安徽马鞍山绿松石中水的结构特征进行红外吸收光谱和激光拉曼光谱分析研究,结果表明:绿松石中部分水分子与Cu2+结合成[Cu(H2O)4]2+水合离子,并在很大程度上制约了绿松石的颜色;马鞍山地区绿松石中结晶水的脱失温度约为303℃～310℃,结构水的脱失温度约为346℃～375℃。绿松石中H2O,OH-的振动是导致其水的激光拉曼光谱形成的主要原因,ν(OH)振动导致的强拉曼特征谱峰在3470 cm-1,3502 cm-1～3505 cm-1之间的弱谱峰则隶属3470 cm-1的次级谱峰,ν(H2O)的拉曼谱峰主峰位于3442 cm-1～3449 cm-1处。由ν(MFe,Cu-H2O)伸缩振动致平缓的拉曼谱峰主要分布在3074 cm-1～3303 cm-1附近。

The infrared absorption spectrum and Raman spectrum have been employed to study the characters of water structure in the turquoise from Ma＇anshan turquoise deposit, Anhui Province. Experiment under room temperature and variational temperature indicated that the turquoise contained hydroxy （Al-OH） with stronger hydrogen bond, hydroxonium [Cu （ H2O）4]^2＋ , and a small quantity of absorption water. The Raman spectra peaks at 3 507 cm^-1 and 3 465 cm 1（±1 cm^-1）are mainly induced by stretching vibrations of ν（A1--OH） and the Raman spectra peaks at 3 285 cm^-1 and 3 074 cm^-1 （_±2 cm^-1） are mainly induced by stretching vibrations of the ν（M CuH2O） and have their specifically displacement positions in Raman spectra. Based on above study, combined with crystal chemistry, temperature dependent infrared absorption spectrum and different thermal analysis, existent form and combinative pattern of the water in turquoise and its con- straint to the color of turquoise have been discussed.