Unit cell parameters and densities of non-doped and 2mol% Y2O3 doped orthorhombic (high pressure form) ZrO2.

Unit cell parameters of non-doped ZrO2 (monoclinic + orthorhombic: high pressure form) and 2 mol% Y2O3 doped ZrO2 (monoclinic + orthorhombic + tetragonal) samples obtained by high pressure experiments were refined, together with those of starting materials, by the technique of whole-powder-pattern fitting without reference to a structural model. The monoclinic-to-orthorhombic transformation of ZrO2 accompanies the increase of density by 0.25 to 0.26 g/cm3. The tetragonal form has a slightly higher density than the orthorhombic form: the difference between the two phases is only 0.03 g/cm3.