Quinary axis: an element of symmetry that occurs in molecules and quasicrystals - a didactic experiment of crystallography

Quimica nova

Baptista, Luis Andre¹  Freitas, Darcson Vieira de¹  Neves, Paulo Cesar Pereira das¹ 

[1] Universidade Luterana do Brasil, Canoas, Brasil

关键词: quinary axis;    molecular symmetry;    quasicrystals.;   

DOI  :  10.1590/S0100-40422010000900028

学科分类：化学（综合）

来源: Sociedade Brasileira de Quimica

【 摘 要 】

Axis of quinarysymmetry occur in molecular symmetry, as in the case of fullerenes, and in crystallinesymmetry, in the quasicrystals. Minerals with pentagonal faces do not have thiselement of symmetry, as the pyrite (FeS2) which shows a ridge thatis different from the other ones, in any face of the crystal. The purpose ofthis paper is to demonstrate conceptual differences between pyritohedron andregular pentagonal dodecahedron symmetries, discussing students' difficultiesto identify them. Also is proposed a didactic experiment with spatial modelsof the above-mentioned forms and the demonstration of its symmetries in clinographicprojections.

【 授权许可】

CC BY