This paper summarizes the new developments in the study of barium rare-earthfluor-carbonate mineral structures.The second order superstructure of cebaite-（Ce）was solved by using high power X—ray single crystal diff...This paper summarizes the new developments in the study of barium rare-earthfluor-carbonate mineral structures.The second order superstructure of cebaite-（Ce）was solved by using high power X—ray single crystal diffractometer.Five kinds ofcoordination forms were found.All atoms in the cell,including C and F,were properlylocated.In the process of study in a cordylite-（Ce）,a new mineral was discovered,whose chemical formula is（Ca<sub>0</sub>.5□<sub>0</sub>.5 ）BaCe<sub>2</sub> （CO<sub>3</sub>）<sub>4</sub>F.It is isostructural withbaiyuneboite-（Ce）,but different in composition（Na in baiyuneboite-（Ce）is substi-tuted by Ca disorderly）.On the basis of the studies a proposal to re-definecordylite-（Ce）as a mineral group name is put forth by the authors.Finally a newtype of twinning of huanghoite—（Ce）was found on the systematical absence ofdiffraction data by means of a single crystal diffractometer.展开更多
Ba-REE fluorcarbonate minerals from a carbonatite dyke at Bayan Obo, Inner Mongolia, North China, are first reported in this contribution, in which chemical composition, rare earth element (REE) patterns, and intergro...Ba-REE fluorcarbonate minerals from a carbonatite dyke at Bayan Obo, Inner Mongolia, North China, are first reported in this contribution, in which chemical composition, rare earth element (REE) patterns, and intergrowth relationships for these minerals have been investigated. Syntactic intergrowth or syntaxy between cebaite and cordylite, as well as cordylite and huanghoite were observed. This syntactic texture resulted from the variation of chemical composition of crystallizing agents for those minerals that crystallized directly from carbonatite magmas. It is worth noting that REE patterns of the Ba-REE fluorcarbonate minerals in the dyke are similar to those of the corresponding minerals from the ore hosted dolomite marble of the Bayan Obo giant REE-Nb-Fe mineral deposit, which implies their relation in origin.展开更多
文摘This paper summarizes the new developments in the study of barium rare-earthfluor-carbonate mineral structures.The second order superstructure of cebaite-（Ce）was solved by using high power X—ray single crystal diffractometer.Five kinds ofcoordination forms were found.All atoms in the cell,including C and F,were properlylocated.In the process of study in a cordylite-（Ce）,a new mineral was discovered,whose chemical formula is（Ca<sub>0</sub>.5□<sub>0</sub>.5 ）BaCe<sub>2</sub> （CO<sub>3</sub>）<sub>4</sub>F.It is isostructural withbaiyuneboite-（Ce）,but different in composition（Na in baiyuneboite-（Ce）is substi-tuted by Ca disorderly）.On the basis of the studies a proposal to re-definecordylite-（Ce）as a mineral group name is put forth by the authors.Finally a newtype of twinning of huanghoite—（Ce）was found on the systematical absence ofdiffraction data by means of a single crystal diffractometer.
文摘Ba-REE fluorcarbonate minerals from a carbonatite dyke at Bayan Obo, Inner Mongolia, North China, are first reported in this contribution, in which chemical composition, rare earth element (REE) patterns, and intergrowth relationships for these minerals have been investigated. Syntactic intergrowth or syntaxy between cebaite and cordylite, as well as cordylite and huanghoite were observed. This syntactic texture resulted from the variation of chemical composition of crystallizing agents for those minerals that crystallized directly from carbonatite magmas. It is worth noting that REE patterns of the Ba-REE fluorcarbonate minerals in the dyke are similar to those of the corresponding minerals from the ore hosted dolomite marble of the Bayan Obo giant REE-Nb-Fe mineral deposit, which implies their relation in origin.
