Synthesis and structural transformations of the “glaserite” type zirconosilicate Na3−xH1+xZrSi2O8·yH2O

A hydrous sodium zirconosilicate material with “glaserite” type structure and generalized formula Na3−xH1+xZrSi2O8·yH2O, 0 < x < 3, 0 < y < 1 is synthesized in the system Na2O:ZrO2:SiO2:H2O at 200 °C. Its crystal structure is composed of zirconium and silicon polyhedra connected to build layers additionally stacked to form 3D zipper-like network. Within the network there are cavities interconnected to channels with irregular shapes where the sodium atoms and water molecules reside. It is found that with synthesis duration the crystal structure gradually transforms from higher symmetrical into triclinic one. The structure of the triclinic form – Na3HZrSi2O8·0.4H2O was refined from powder diffraction data. It crystallizes in the space group P-1 with lattice parameters a = 9.05234, b = 5.56121, c = 6.96219 Å, α = 92.178, β = 90.839, γ = 90.288°. To the best of our knowledge the studied compound is the only water-containing material with “glaserite” type structure.