采用中红外光谱(MIR)研究钨酸钠分子结构。钨酸钠分子红外吸收模式主要包括W—O键不对称伸缩振动模式和W—O键对称伸缩振动模式等。采用变温中红外光谱(TD-MIR)研究温度对钨酸钠分子结构的影响。在303~573 K的温度范围内,随着测定温度的升高,钨酸钠分子ν_as-W-O和ν_s-W-O对应的红外吸收频率和强度均发生明显的改变。以ν_as-W-O和ν_s-W-O为研究对象,采用二维中红外光谱(2D-MIR)研究钨酸钠分子的热变性。研究发现,在303~373、383~463、473~573 K 3个温度区间,钨酸钠分子主要官能团(ν_as-W-O和ν_s-W-O)对热敏感程度及变化快慢顺序都存在较大差异,并进一步进行了热变性机理的研究。本研究拓展了中红外光谱技术(MIR、TD-MIR和2D-MIR)在重要的稀有金属盐(钨酸钠)分子结构及热变性领域的研究范围。

Molecular structure of sodium tungstate is characterized by means of mid infrared spectroscopy (MIR).The infrared absorption modes of sodium tungstate molecular include W—O bond asymmetry stretch vibration (ν_as-W-O),W—O bond symmetrical stretch vibration (ν_s-W-O),etc.The influences of temperature on sodium tungstate molecular structure is studied by means of temperature-dependent mid infrared spectroscopy (TD-MIR).It is found that with the increasing temperature in the range of 303-573 K,the corresponding infrared absorption frequency and intensity of sodium tungstate molecular (ν_as-W-O and ν_s-W-O) change obviously.Taking ν_as-W-O and ν_s-W-O as study objects,the thermal denaturation of sodium tungstate molecular are explored by using two-dimensional mid infrared spectroscopy (2D-MIR).It is indicated that in the 303-373 K,383-463 K and 473-573 K temperature ranges,the main functional groups of sodium tungstate molecular (ν_as-W-O and ν_s-W-O) show significant differences in thermal sensitivity and the speed order of change.The thermal denaturation mechanism of sodium tungstate is further studied.In a sum,this study expands the research scope of mid infrared spectroscopy techniques (MIR,TD-MIR and 2D-MIR) in the molecular structure and thermal denaturation of important rare metal salts (sodium tungstate).