材料科学基础课程晶体结构概念上现存误区的探讨

Concept Misunderstanding of Crystal Structure in the Course of Foundations of Materials Science

根据晶体存在的平移对称性和点对称性可用点阵和晶系对其分类。在教学实践中如果不注意区分这两类对称性的差异,就会造成学生在理解晶体结构概念时的误区,对后续深入的学习和新材料的研究造成困扰。现有材料科学基础课程教学中代表性的非严谨表达为:"根据晶胞的6个参数可以把14种空间点阵归纳为七大晶系"。分析并阐述了恰当的晶体结构概念,以克服上述困扰。

Lattice and crystal system are used to classify crystals according their translation symmetry and point symmetry which exist. Certain misunderstanding of students on the concept of crystal structure will be induced if enough attention has not been paid to the difference between the two symmetries, which may lead to confusion and difficulty during further study and research of many advanced materials. A typical unprecise description in the lecture of foundations of materials science is that ＂the 14 space lattices could be reduced to seven crystal systems according to six parameters of the crystal cell＂, In contrary to that, a proper analysis and expatiation concerning the conceot of crystal structure is given, which may helo to overcome the confusion and difficulty above.