摘要
利用CCD单晶衍射仪对草莓红绿柱石进行晶体结构测定,测定其空间群为R3c,并讨论了结构中Li+有序地置换Be2+造成c/a值的变化特征。晶体中发现复三方偏三角面体的负晶包裹体,其宏观对称属m,它与空间群Rc相对应,但与测出晶体结构的空间群有矛盾。X射线结构测定已否定了其空间群为Rm的看法。要解决草莓红绿柱石晶体空间群是否有对称中心(Rc或Rc)的问题,还需进一步将X射线结构的数据及其有关的电性实验结合分析。
CCD single-crystal X-ray diffractometer was employed to analyze the crystal structure of pezzottaite with space group = R3c. The variation characteristics of c/a ratio of unit celt, which is caused by the regular replacement of Li^＋ to Be^2 ＋ in the structure, has been discussed. In contrast with the detected space group of the crystal, the newly discovered ditrigonal scalenohedral negative crystal inclusions showed the m symmetry of the crystal with space group symmetry R^-3c. Our structural analysis of pezzottaite revealed that the previous assumption of the space group （R^-3m） of the crystal was incorrect. Further experiments are required to determine the true space group （R3c or R^-3c） of pezzottaite and reveal whether it has the symmetrical centre or not.
出处
《矿物学报》
CAS
CSCD
北大核心
2008年第4期350-356,共7页
Acta Mineralogica Sinica
基金
国家自然科学基金项目(批准号:49872022)
