Evidence of reaction intermediates in microwave-assisted synthesis of SHG active α-La(IO 3 ) 3 nanocrystals

Sylvain Regny (1) , Yan Suffren (2) , Olivier Leynaud (3) , Isabelle Gautier-Luneau (1) , Géraldine Dantelle (1)

1 NEEL - OPTIMA - Optique et Matériaux
2 ISCR - Institut des Sciences Chimiques de Rennes
3 NEEL - X'Press - X'Press : diffraction et hautes pressions

We explore here how, under microwave assisted hydrothermal process, various synthesis conditions influence the formation of different lanthanum iodate compounds: α-La(IO3)3, La(IO3)3(H2O), La(IO3)3(HIO3) and La(IO3)2.66(OH)0.66. Whatever the intial [La 3+ ]:[IO3-] ratio, α-La(IO3)3 crystallizes if the synthesis temperature exceeds 220°C. Phase transformations in solid state or under hydrothermal synthesis are also discussed. Interestingly, we evidence the full phase transformation under hydrothermal synthesis from the new hydrate form La(IO3)3(H2O) into stable and optically active α-La(IO3)3 through an appropriate hydrothermal process. This evolution can be explained by structural rearrangements of the coordination sphere of lanthanum atoms, stabilizing the structure.

Domaines: Matériaux

Sylvain Regny, Yan Suffren, Olivier Leynaud, Isabelle Gautier-Luneau, Géraldine Dantelle. Evidence of reaction intermediates in microwave-assisted synthesis of SHG active α-La(IO 3 ) 3 nanocrystals. CrystEngComm, 2020, 22 (14), pp.2517-2525. ⟨10.1039/D0CE00156B⟩. ⟨hal-02545589⟩