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

► Hydrothermal synthesis of hydrous zirconosilicate Na3HZrSi2O8·0.5H2O is reported. ► Gradual symmetry lowering is observed upon synthesis treatment. ► This compound's modifications possess “glaserite”-type structure. ► This is a rare case of water-containing material with “glaserite”-type structure.