skip to main content

Title: Crystal-structure refinement of zirconium-rich eudialyte and its place among calcium-poor eudialyte-group minerals

The repeated refinement of the crystal structure of zirconium-rich eudialyte based on the X-ray diffraction data set collected earlier revealed new structural features. The trigonal unit-cell parameters are a = 14.222(3) A, c = 30.165(5) A, V = 5283.9 A{sup 3}. The refinement resulted in the reduction of the R factor from 0.045 (2347F > 4{sigma}(F)) to 0.035 (3124F > 3{sigma}(F)). It was found that the ordering of Ca and Fe in six-membered rings leads to the lowering of the symmetry to R3. An excess amount of zirconium (more than three atoms per symmetrically independent unit) is located in the M2 microregion in square and five-vertex polyhedral positions. However, this amount is insufficient to be dominant, and the deficiency of zirconium is compensated for by sodium atoms. Based on the new data, zirconium-rich eudialyte can be assigned to the oneillite subtype, being a zirconium-rich and aluminum variety of raslakite.
Authors:
;  [1]
  1. Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)
Publication Date:
OSTI Identifier:
22210531
Resource Type:
Journal Article
Resource Relation:
Journal Name: Crystallography Reports; Journal Volume: 58; Journal Issue: 5; Other Information: Copyright (c) 2013 Pleiades Publishing, Ltd.; http://www.springer-ny.com; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CALCIUM; CRYSTAL STRUCTURE; SILICATE MINERALS; X-RAY DIFFRACTION; ZIRCONIUM