Synthesis, crystal and electronic structures of two novel tunnel bismuth oxychlorides Bi18O22Cl8.5(BO3)0.5 and Bi18O22Cl8Se.

Single crystals of two new quaternary bismuth oxychlorides, Bi 18 O 22 Cl 8.5 (BO 3) 0.5 (1) and Bi 18 O 22 Cl 8 Se (2) , have been serendipitously produced in syntheses starting from bismuth borate or oxyselenide and oxychloride. The crystal structure of 1 represents a high symmetry analog of the PbBi 17 O 22 Cl 9 type structure, formed by double aliovalent (Pb2+ → Bi3+, 0.5Cl– → 0.5BO 3 3−) substitution at the two respective cationic and anionic sites, while 2 is a full structural analog of PbBi 17 O 22 Cl 9. Overall, their structures can be described as sequences of thick (16 Å) slabs (2D "host" structure) comprised of litharge–like layers and ribbons formed by edge-sharing oxocentered OBi n , polyhedra (n = 4 and 5). The chloride anions fill the 7.6 Å channels with the triangular cross-section inside the slabs as well as the interlayer space wherein they are partially substituted by disordered BO 3 3− groups or Se2− anions. Compound 1 is just the second example of a mixed halide–borate occupancy among bismuth compounds while 2 illustrates much broader perspectives of mixed oxyhalide–oxychalcogenide approach to construction of novel complex bismuth compounds. Both compounds make new contributions to the family of tunnel structures of anion-centered tetrahedra featuring wide trigonal channels filled by halide anions or more complex metal–halide "salt inclusions". Topology of the channels in the tunnel bismuth oxychlorides. [Display omitted] • Single crystals of two new quaternary bismuth oxychlorides, Bi 18 O 22 Cl 8.5 (BO 3) 0.5 and Bi 18 O 22 Cl 8 Se were obtained and studied. • The crystal chemistry of microporous tunnel bismuth oxychlorides is discussed. • "The modularity of the channels and topologies are characterized," [ABSTRACT FROM AUTHOR]