posted on 2017-06-23, 20:13authored byYi-Gang Chen, Nan Yang, Xing-Xing Jiang, Yao Guo, Xian-Ming Zhang
The first lead tellurate–nitrate
nonlinear-optical (NLO)
crystal, Pb9Te2O13(OH)(NO3)3, featuring a 3D anionic diamondlike toplogical structural
motif formulated as [Pb9O13]8– constructed by unique nonanuclear basket-shaped Pb@Pb8O14 clusters has been hydrothermally achieved, in which
the Pb@Pb8O14 cluster shows a core–shell
structure with one PbO10 polyhedron enclosed by eight PbOx (x = 3 and 4) polyhedera
via edge and face sharing. The hexavalent Te in TeO5(OH)
octahedra is linked to a [Pb9O13]8– cluster to form a rare [Pb9Te2O13(OH)]3+ cationic framework. The compound demonstrates
a powder second-harmonic-generation (SHG) response of about 1.2 times
that of KH2PO4 (KDP) as well as a wide transparency
range. Calculations on the local dipole moment and SHG coefficient
reveal that the net polarization is zero because of a Kleinman-forbidden
point group. Further analysis shows that the SHG response results
from structure-induced variations by thermal vibrations of the lattice
rather than the intrinsic dipole moment, which offers another insight
on the design of new NLO materials.