台湾碧玉的X射线粉末衍射和红外吸收光谱特征

XRD and IR Spectra Study on Green Nephrite from Taiwan

在综合利用前人研究成果的基础上,通过对产自台湾花莲的碧玉进行扫描电子显微镜(SEM)、X射线粉末衍射(XRD)和傅里叶变换红外光谱分析(FTIR)等测试分析,并与加拿大碧玉的相关研究成果进行比较分析。研究结果表明,台湾碧玉的主要矿物组成为透闪石,并且存在少量阳起石、绿泥石等杂质矿物。透闪石呈显微纤维状结构,纤维沿长轴方向密集排列,相互穿插;通过XRD计算其晶胞参数,透闪石的结晶度较高,达到94.62%;与加拿大碧玉相比,台湾碧玉中的Fe2+质量分数较高;在红外光谱中,3 674cm-1附近的吸收谱带属于透闪石中OH伸缩振动,900～1 150cm-1范围内吸收谱带属于Si4O11的伸缩振动,600～800cm-1范围内吸收谱带归属于γs(Si-O-Si)振动,400～600cm-1范围内吸收谱带属于Si-O弯曲振动、M-O伸缩振动和OH平动的耦合。

Based on the former research results, the green nephrite from Taiwan has been ex- perimented by SEM, XRD and FTIR and the experimental results are compared with the green nephrite from Canada. The results indicate that the green nephrite from Taiwan mainly consists of tremolite, small amounts of actinolite and chlorite. The tremolite shows fibrous structure under microscope which arrays intensively along the macro-axis and interweaved closely. Cell parameters of the green nephrite from Taiwan calculated by XRD show that the crystallinity goes up to 94.62%. Besides, the content of Fe^2＋ in the green nephrite from Tai-wan is much higher than that in the green nephrite from Canada. Among IR spectra, the bands near3 6 7 4 cm^-1 identify the band of OH stretching vibration , the bands near 9 0 0 - 1 1 5 0 cm^-1 identify Si40n stretching vibration, the bands near 600-800 cm^-1 identify the 7s（Si-O-Si） vibration, the bands near 400-600 cm^-1 identify the coupling of Si-O bending vibra-tion, Mg-O stretching vibration and OH parallel vibration.