Abstract

A new niobium-rich lomonosovite variety with a high degree of ordering of Ti and Nb atoms has been investigated by X-ray diffraction analysis and electron probe microanalysis. Its simplified formula is Na₁₀Ti₂(Nb,Fe,Ti)₂(Si₂O₇)₂(PO₄)₂O₄. The triclinic unit-cell parameters are a = 5.411(1) Å, b = 7.108(1) Å, c = 14.477(2) Å, α = 99.78(1)°, β = 96.59(1)°, γ = 90.26(1)°, V = 544.94(5) ų, Z = 1, sp. gr. P1. The crystal structure has been refined to the final reliability factor R = 6.3% within the anisotropic approximation of atomic displacements using 3674 reflections with F > 3σ(F). The problem of niobium distribution in minerals with structures of lomonosovite and related types is discussed.

中文翻译：

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Khibiny地块（可乐半岛）中富含对称性P 1的富铌菱锰矿的晶体结构

摘要

通过X射线衍射分析和电子探针显微分析，研究了一种新的富含铌的，具有高度有序的Ti和Nb原子的菱锰矿。其简化公式为Na ₁₀ Ti ₂（Nb，Fe，Ti）₂（Si ₂ O ₇）₂（PO ₄）₂ O ₄。三斜晶胞参数为a = 5.411（1）Å，b = 7.108（1）Å，c = 14.477（2）Å，α= 99.78（1）°，β= 96.59（1）°，γ= 90.26 （1）°，V = 544.94（5）³，ž = 1，SP。gr。P1.使用F >3σ（F）的3674次反射，在原子位移的各向异性近似下，晶体结构已精炼到最终可靠性因子R = 6.3％。讨论了含钠蒙脱石及相关类型矿物中铌的分布问题。