화학공학소재연구정보센터
Inorganic Chemistry, Vol.56, No.15, 9019-9024, 2017
A(II)GeTeO6 (A = Mn, Cd, Pb): Non-Centrosymmetric Layered Tellurates with PbSb2O6-Related Structure
A(II)GeTeO6 (A = Mn, Cd, Pb), new non-centrosymmetric (NCS) honeycomb-layered tellurates, were synthesized and characterized. A(II)GeTeO6 (A = Mn, Cd, Pb) crystallize in trigonal space group P312 (No. 149) of edge-sharing Ge4+O6 and Te6+O6 octahedra, which form honeycomb-like-layers in the ab-plane with A(II) (A = Mn, Cd, Pb) cations located between the layers. Their crystal structures are PbSb2O6-related, and the ordering of Ge4+ and Te6+ in octahedral environment breaks the inversion symmetry of the parent PbSb2O6 structure. The size of A(II) cation in six coordination is an important factor to stabilize PbSb2O6-based structure. Temperature dependent optical second harmonic generation measurements on A(II)GeTeO6 confirmed non-centrosymmetric character in the entire scanned temperature range (0 to 600 degrees C). The materials exhibit a powder SHG efficiency of similar to 0.37 and similar to 0.21 times of KH2PO4 for PbGeTeO6 and CdGeTe06, respectively. Magnetic measurements of MnGeTeO6 indicate anti-ferromagnetic order at T-N approximate to 9.4 K with Weiss temperature of -22.47 K.