  We have synthesized a new layered oxychalcogenide La2O2Bi3AgS6. From
synchrotron X-ray diffraction and Rietveld refinement, the crystal structure of
La2O2Bi3AgS6 was refined using a model of the P4/nmm space group with a =
4.0644(1) {\AA} and c = 19.412(1) {\AA}, which is similar to the related
compound LaOBiPbS3, while the interlayer bonds (M2-S1 bonds) are apparently
shorter in La2O2Bi3AgS6. The tunneling electron microscopy (TEM) image
confirmed the lattice constant derived from Rietveld refinement (c ~ 20 {\AA}).
The electrical resistivity and Seebeck coefficient suggested that the
electronic states of La2O2Bi3AgS6 are more metallic than those of LaOBiS2 and
LaOBiPbS3. The insertion of a rock-salt-type chalcogenide into the van der
Waals gap of BiS2-based layered compounds, such as LaOBiS2, will be a useful
strategy for designing new layered functional materials in the layered
chalcogenide family.
