The crystal structure of radiation-damaged natural zircon was studied. An anisotropic unit-cell swelling which was observed in the early stages of amorphization (0.17% along the a-axis, 0.62% along the c-axis) was attributed to an anisotropy of the expansion of ZrO8 polyhedra. Larger anisotropic displacement parameters were found for Zr and O atoms; thus indicating that the distortion which was produced by particle-induced localized defects mainly affected the ZrO8 units. The overall shape of SiO4 tetrahedra remained essentially undistorted, while Si-O bonds were found to lengthen by 0.43%.

Localized Defects in Radiation-Damaged Zircon. S.Rios, T.Malcherek, E.K.H.Salje, C.Domeneghetti: Acta Crystallographica B, 2000, 56[6], 947-52