Syntheses, crystal structures, and optical properties of Pb6B3O10X (X=F, Cl, Br)

A series of lead-containing halogen oxyborates, Pb 6 B 3 O 10 X ( X =F, Cl, Br), have been grown by high-temperature solution method and their crystal structures were determined by single-crystal X-ray diffraction. They are isostructural and crystallize in the space group Pbcm of the orthorhombic crystal system . The crystal structures are dominated by one-dimensional ∞ [(Pb 4 O)(BO 3 ) 3 ] “ Zig-Zag ”-chains, while the remaining Pb atoms and X ( X =F, Cl, Br) atoms are filled to balance the charge. Compared with the previously reported compound Pb 4 O(BO 3 ) 2 (the molecular formula Pb 4 O(BO 3 ) 2 can be regarded as Pb 6 B 3 O 10.5 ) with the space group Aba 2, the structures of Pb 6 B 3 O 10 X ( X =F, Cl, Br) are completely different from that of Pb 4 O(BO 3 ) 2 . IR spectroscopy , UV–vis-NIR diffuse reflectance spectroscopy , thermal analysis, and theoretical calculations were also performed on the reported materials.