Li2BaSc(BO3)2F and LiBa2Pb(BO3)2F with Layered Structures featuring Special Li-O/F Configurations

Two new borate fluorides, Li2BaSc(BO3)(2)F and LiBa2Pb(BO3)(2)F, with layered structures featuring special Li-O/F configurations have been successfully prepared by the high-temperature solution method. Li2BaSc(BO3)(2)F contains the first reported (2)(infinity)[Li-2(BO3)(2)F] double layers that are evolved from (2)(infinity)[Be2BO3F2] single layers in KBe2BO3F2 through substituting BeO4 with the LiO3F tetrahedra. The adjacent double layers are tightly connected by strong Sc-O bonds, generating the strongest interlayer bond and smallest interlayer distance among KBe2BO3F2 derivatives with double-layered structures. LiBa2Pb(BO3)(2)F features (2)(infinity)[Li(BO3)(2)F] single layers built up of special LiO4F2 octahedra and the BO3 triangles. To our best knowledge, the LiO4F2 octahedron is observed for the first time in borates. Besides, the LiO4F2 octahedra construct unique (1)(infinity)[LiO4F] straight chains through sharing apical F atoms, which is different from the configurations of the similar six-coordinated LiO6 octahedra in other borates.