A multi-methodological study was conducted in order to provide further insight into the structural and compositional complexity of rare earth element (REE) fluorcarbonates, with particular attention to their correct assignment to a mineral species. Polycrystals from La Pita Mine, Municipality de Maripí, Boyacá Department, Colombia, show syntaxic intergrowth of parisite–(Ce) with röntgenite–(Ce) and a phase which is assigned to B3S4 (i.e., bastnäsite-3–synchisite-4; still unnamed) fluorcarbonate. Transmission electron microscope (TEM) images reveal well-ordered stacking patterns of two monoclinic polytypes of parisite–(Ce) as well as heavily disordered layer sequences with varying lattice fringe spacings. The crystal structure refinement from single crystal X-ray diffraction data – impeded by twinning, complex stacking patterns, sequential and compositional faults – indicates that the dominant parisite–(Ce) polytype M1 has space group Cc. Parisite–(Ce), the B3S4 phase and röntgenite–(Ce) show different BSE intensities from high to low. Raman spectroscopic analyses of parisite–(Ce), the B3S4 phase and röntgenite–(Ce) reveal different intensity ratios of the three symmetric CO3 stretching bands at around 1100 cm−1. We propose to non-destructively differentiate parisite–(Ce) and röntgenite–(Ce) by their 1092 cm−1 / 1081 cm−1 ν1(CO3) band height ratio.

中文翻译：

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Parisite– (Ce) 之谜：氟碳酸盐矿物鉴定的挑战

进行了多方法研究，以进一步了解稀土元素 (REE) 氟碳酸盐的结构和组成复杂性，特别注意它们对矿物种类的正确分配。来自哥伦比亚博亚卡省马里皮市 La Pita 矿的多晶显示了 parisite-(Ce) 与 röntgenite-(Ce) 的句法共生和分配给 B3S4 的相（即，bastnäsite-3-synchisite-4；仍然未命名）氟碳酸盐。透射电子显微镜 (TEM) 图像显示了两种单斜多型硅酸盐 - (Ce) 的有序堆叠模式以及具有不同晶格条纹间距的严重无序层序列。单晶 X 射线衍射数据的晶体结构细化 - 受到孪晶、复杂堆叠模式的阻碍，连续和组合断层 - 表明主要的平行位点 - (Ce) 多型 M1 具有空间群 Cc。Parisite– (Ce)、B3S4 相和伦铁矿– (Ce) 从高到低显示出不同的 BSE 强度。parisite– (Ce)、B3S4 相和菱铁矿– (Ce) 的拉曼光谱分析揭示了三个对称 CO3 伸缩带在 1100 cm - 1 附近的不同强度比。我们建议通过它们的 1092 cm − 1/1081 cm − 1 ν1 (CO3) 带高比非破坏性地区分 parisite– (Ce) 和 röntgenite– (Ce)。B3S4 相和 röntgenite– (Ce) 揭示了三个对称 CO3 伸缩带在 1100 cm - 1 附近的不同强度比。我们建议通过它们的 1092 cm − 1/1081 cm − 1 ν1 (CO3) 带高比非破坏性地区分 parisite– (Ce) 和 röntgenite– (Ce)。B3S4 相和 röntgenite– (Ce) 揭示了三个对称 CO3 伸缩带在 1100 cm - 1 附近的不同强度比。我们建议通过它们的 1092 cm − 1/1081 cm − 1 ν1 (CO3) 带高比非破坏性地区分 parisite– (Ce) 和 röntgenite– (Ce)。