Rietveld refinement of the crystal structures of Rb2 XSi5O12 (X = Ni, Mn)

Area of Science:

• Inorganic Chemistry
• Crystallography
• Materials Science

Background:

• Leucite silicate frameworks are important structural motifs in various materials.
• Understanding cation ordering and disorder is crucial for predicting material properties.

Purpose of the Study:

• To synthesize and characterize novel synthetic leucite silicate framework analogues.
• To investigate the crystal structure and cation distribution in Rb2NiSi5O12 and Rb2MnSi5O12.

Main Methods:

• High-temperature solid-state synthesis.
• X-ray powder diffraction (XRPD) data collection using Cu Kα radiation.
• Rietveld refinement for crystal structure determination.

Main Results:

• The compounds Rb2NiSi5O12 and Rb2MnSi5O12 were successfully synthesized.
• Both compounds crystallize in the space group Pbca, adopting a cation-ordered leucite structure.
• Rietveld refinements indicated ordered silicon and X (Ni or Mn) atoms on separate tetrahedral sites.
• Analysis of the nickel-containing sample suggests possible T-site cation disorder.

Conclusions:

• The study successfully synthesized and characterized two new synthetic leucite analogues.
• The cation-ordered structure was confirmed, but potential disorder in Rb2NiSi5O12 warrants further investigation.
• These findings contribute to the understanding of structure-property relationships in silicate frameworks.