Bafertisite is the first new mineral found in the Bayan Obo iron mine, Inner Mongolia, China. To date, it has been over half a century, but the expression concerned with the formula of type befertisite and unit-cell parameters are still controversial, some even very different. This study compiled all the expressions related to the formula. Combined with the structural refinements of type bafertisite and minerals alike conducted home and abroad and the preliminarily-published chemical compositions, we calculated and re-evaluated atoms per formula unit (apfu) using three calculation methods. Based on this research, the crystal chemical formula of type bafertisite was improved tentatively. In addition, the unit-cell parameters are also in dispute. Based on the preliminary refinement to the crystal structure and enlightenment from crystal structure of the same mineral in East Sea, our improvement to the unit-cell parameters of type bafertisite has solid evidence. Therefore, it is necessary to conduct in-depth research on the type bafertisite. One thing is sure that the crystal chemical formula, unit-cell parameters, and crystal structure need to determination, refinement and modification.%钡铁钛石是白云鄂博REE-Nb-Fe矿发现的首个新矿物.迄今,已逾半个世纪.但是,关于原型钡铁钛石的化学分子式却有不同的表述,有的甚至殊异.拙文对这些写法各异的分子式进行了梳理,结合我们和国内外对原型钡铁石及其类似矿物的晶体结构测定,运用其最初发表的化学成分,按3种方法,重新计算矿物单位分子式中的离子数并分别加以评估.在此基础上,对原型钡铁钛石的晶体化学式作了初步改进.再者,关于原型钡铁钛石的晶胞参数,国内外亦存在歧见.主要根据晶体结构初步精修,借鉴东海产钡铁钛石晶体结构精测的启示,对原型钡铁钛石的真晶胞参数作了持之有据的推论.看来,原型钡铁钛石仍有深入研究的必要.可以肯定,它的晶体化学式、晶胞参数和晶体结构需要厘正、辩正和修正.
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