New iodate materials as potential laser matrices. Preparation and characterisation of α-M(IO3)3 (M = Y, Dy) and β-M(IO3)3 (M = Y, Ce, Pr, Nd, Eu, Gd, Tb, Dy, Ho, Er). Structural evolution as a function of the Ln3+ cationic radius

Anhydrous yttrium iodate presents polymorphism; two crystalline phases are obtained under hydrothermal conditions. α-Y(IO3)3 crystallises in the monoclinic space-group P21/c with a three-dimensional structure, whereas β-Y(IO3)3 crystallises in the monoclinic space-group P21/n with a two-dimensional structure. The lattice parameters are a = 7.038(1) Å, b = 8.466(1) Å, c = 13.317(1) Å, β = 99.65(1)°, V = 782.3(2) Å3, Z = 4 for α-Y(IO3)3 and a = 8.685(1) Å, b = 5.964(1) Å, c = 14.958(1) Å, β = 96.99(2)°, V = 769.0(2) Å3, Z = 4 for β-Y(IO3)3. The α-form is isostructural with α-Dy(IO3)3 studied in this work and α-Ln(IO3)3 (Ln = Ce, Pr, Nd, Sm, Eu, Gd, Tb, Ho, Er, Tm, Yb, and Lu) already studied. The β-form is isostructural with β-Ln(IO3)3 (Ln = Ce, Pr, Nd, Eu, Gd, Tb, Dy, Ho and Er) studied in this work. The structural evolutions as a function of the Ln3+ cationic radius are studied. α-Y(IO3)3 and β-Y(IO3)3 present good thermal stability since they decompose at 600 °C. They are transparent up to 11.5 μm and they have good optical damage thresholds on powder.

Anhydrous yttrium iodates present dimorphism: α-Y(IO3)3 and β-Y(IO3)3 having two and tri-dimensional structures, respectively.Figure optionsDownload as PowerPoint slide