Introducing Pb²⁺ cations with lone pair electrons in borates is efficient to form multiple crystalline forms. Here, we report two new compounds, α-Pb₄B₂O₇ and β-Pb₄B₆O₁₃, which exhibit different crystal forms from the previously reported lead borates, β-Pb₄B₂O₇ and α-Pb₄B₆O₁₃, respectively. Two sets of polymorphs: α-, β-Pb₄B₂O₇ and α-, β-Pb₄B₆O₁₃, exhibit completely different crystal structures and diverse optical properties. Thermal gravimetric and differential scanning calorimetry (TG-DSC) and variable-temperature powder X-ray diffraction (XRD) analyses were performed to study their thermodynamic stabilities. Structure-property relationships were discussed through first-principles calculation. Notably, the new phases, α-Pb₄B₂O₇ and β-Pb₄B₆O₁₃, have larger birefringence than their corresponding polymorphs due to the rearrangement of the functional groups in their structures.

用硼酸根中的孤对电子引入Pb ²⁺阳离子可有效形成多种晶体形式。这里，我们报告了两个新的化合物，α-铅₄乙₂ ö ₇和β-铅₄乙₆ ø ₁₃，其从先前报道的铅硼酸盐，β-铅表现出不同的晶体形式₄乙₂ ö ₇和α -铅₄ B ₆ O ₁₃。两组多晶型物：α-，β-铅₄乙₂ ö ₇和α-，β-铅₄乙₆ Ô ₁₃呈现完全不同的晶体结构和多样的光学特性。进行了热重分析和差示扫描量热法（TG-DSC）以及变温粉末X射线衍射（XRD）分析，以研究其热力学稳定性。通过第一性原理的计算，讨论了结构-属性之间的关系。值得注意的是，新的相，α-铅₄乙₂ ö ₇和β-铅₄乙₆ ø ₁₃，具有比其相应的多晶型物更大的双折射，由于官能团的它们的结构重排。