Rietveld refinement of Ba(5)(AsO(4))(3)Cl from high-resolution synchrotron data

Area of Science:

• Materials Science
• Inorganic Chemistry
• Crystallography

Background:

• Apatite-type structures are common in various minerals and synthetic materials.
• Halogenoapatites with the general formula A(5)(YO(4))(3)X are known, where A is a divalent cation, Y is a pentavalent cation, and X is a halogen.

Purpose of the Study:

• To synthesize and characterize a novel apatite-type compound, penta-barium tris-[arsenate(V)] chloride (Ba(5)(AsO(4))(3)Cl).
• To determine the crystal structure of the synthesized compound using advanced diffraction techniques.

Main Methods:

• High-temperature ion exchange synthesis using mimetite (Pb(5)(AsO(4))(3)Cl) and barium carbonate.
• High-resolution synchrotron X-ray powder diffraction (XRPD).
• Rietveld refinement for crystal structure analysis.

Main Results:

• Successful synthesis of Ba(5)(AsO(4))(3)Cl via ion exchange.
• Rietveld refinement confirmed the apatite-type structure, space group P6(3)/m.
• The structure features isolated arsenate tetrahedra and barium cations within channels occupied by chloride anions.

Conclusions:

• The synthesized Ba(5)(AsO(4))(3)Cl is a new member of the halogenoapatite family.
• The compound adopts the characteristic apatite structure, consistent with related materials.
• This study contributes to understanding the structural diversity of apatite-type compounds.