Synthesis and characterization of gallo-silicate carbonate cancrinite

Gallosilicate cancrinite with carbonate anion, Na₈[GaSiO₄]₆(CO₃)1.72(H₂O)₅ has been synthesized at low temperature by hydrothermal method (373 K). The white crystalline cancrinite powder was characterized by IR, X-ray powder diffraction, TGA, SEM, and MAS NMR. Crystal structure was refined in the space group P6³, from X-ray powder diffraction data using Rietveld refinement method with a = 12.5899 Å, c = 5.1424 Å. The average Al-O bond distance is 1.8109 Å and Si-O bond distance is 1.5847 Å, while the T-O-T angle is found to be 138.793°. TGA shows thermal behavior of the carbonate anion inside the cancrinite cages. The single resonance line in the ²⁹Si spectrum confirms strictly alternating order of Ga and Si in the framework. The SEM picture shows hexagonal needle shaped structures.