萤石颜色与自由基关系的电子自族共振（ESR）研究

The Study of Electron Spin Resonance(ESR)on the Relationship between Free Radical and Color Flourite

萤石颜色与自由基关系的电子自族共振（ＥＳＲ）研究唐荣炳，温桂兰（中国科学院地球化学研究所，贵阳５５０００２）（中国科学院广州地球化学研究所，广州５１０６４０）关键词萤石，顺磁离子，自由基长期以来，对矿物颜色的研究，先是定性观察和分类，再是应用光的吸收...

The color origin of mineral has been concerned and studied for a long time. A variety of viewpoints has been suggested for the origin mechanism by different methods. We measured and studied different colors of fluorites by using ESR technique and free radical theory. It's found that the variation of fluorite's color is related with the existence foreign paramagnetic ions Mn,Fe etc. Isomophously replacing Ca ion in fluorites. Affected by geological surroundings the process of Mn or Fe ion replaces Ca ion result in electron gaining and lossing in crystal lattice and formed electron─electron hole centers (free radicals in the place of fluorine ion ). The density of free radicals is constrained by the electron gainins and lossing of paramagnetic ions Mn,Fe etc. The color of fluorite varies with the density of free radicals. Therefore, we suggest that the color-forming mechanism in fluorite are: 1)there exist foreign paramagnetic ions (color-forming ions)in the crystal lattice; 2)the variation of color is related with free radicals. Thus,the variation of density of free radical in mineral crystal reflects color-staining and color-fadding of minerals.