Crystal Structure of Niobium-Rich Lomonosovite with Symmetry P1 from the Khibiny Massif (Kola Peninsula) (original) (raw)
NASA/ADS
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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) Å3, 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.
Publication:
Crystallography Reports
Pub Date:
May 2020
DOI:
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