Special _∞¹[OPb₂] Chains and _∞¹[O₂Pb₃] Ribbons Based on OPb₄ Anion-Centered Tetrahedra\nin Pb₂(O₄Pb₈)(BO₃)₃Br₃ and Pb₂(O₈Pb₁₂)(BO₃)₂Br₆

Abstract

The\nstructures of two new lead-containing oxyborate bromines, Pb₂(O₄Pb₈)­(BO₃)₃Br₃ (<b>1</b>) and Pb₂(O₈Pb₁₂)­(BO₃)₂Br₆ (<b>2</b>), are\ndetermined by single-crystal X-ray diffraction for the first time.\nBoth of them crystallize in the space group <i>C</i>2<i>/c</i> of the monoclinic crystal system. Although the two compounds\nhave the same type of fundmental building units (FBUs), the OPb₄ anion-centered tetrahedra and BO₃ triangles, they\nexhibit different connection modes. Compound <b>1</b> consists\nof single _∞¹[OPb₂] chains,\nwhile compound <b>2</b> possesses _∞¹[O₂Pb₃] ribbons. Interestingly, large Br atoms\nprofoundly influence the conformation of polyions based on the OPb₄ anion-centered tetrahedra, resulting in single _∞¹[OPb₂] chains linked up by finite zweier chains\nwith four OPb₄ tetrahedra via the opposite edges in compound <b>1</b> and _∞¹[O₂Pb₃] ribbons with sequential condensation of OPb₂ chains\nin compound <b>2</b>. A detailed description of the effect of\nlarge Br atoms on the conformation of polyions is discussed. IR spectroscopy,\nUV–vis–NIR diffuse reflectance spectroscopy, and thermal\nanalysis are also performed on the reported materials.