Abstract The paper reports a thorough investigation of little inspected two classes of group VIIA based crystals: interhalogen compounds ClF, ClF 3 , BrF 3 and IF 3 on one hand and halogen suboxides F 2 O, Cl 2 O and Br 2 O on the other hand, as well as rare gas fluorides (here exemplarily XeF 4 ), all exhibiting peculiar stereochemistry of electron (non-bonding) lone pairs merging in forms of twins and triplets. Particularly with respect to the well known VSEPR (Valence Shell Electron Pair Repulsion) model we present original approach merging crystal chemistry and density functional theory (DFT) electron localization function (ELF) to provide accurate topologic analyses and precise metrics of electron lone pairs geometries. In this context we rewrite the chemical formulae above by adjoining E designing the lone pair (LP) and M* formulating the LP-bearing element: ClF{E 3 }, M* 2 OE 2 {E 3 } 2 (M* = F, Cl, Br), M*F 3 E 2 (M* = Cl, Br, I) and XeF 4 E 2 . Then in ClF{E 3 } and M* 2 OE 2 {E 3 } 2 (M* = F, Cl, Br) family an original stereochemistry is developed with LP concentration in E triplets which generate electronic torus revolving around Cl and M* which in the neighborhood of largely electronegative F, exhibit cationic-like behavior. E around Cl in ClF and then around M* of the series under consideration exhibits an ellipsoidic shape with an equivalent sphere of influence radius (r E ) increasing along with the atomic number Z, i.e. r E_F = 0.52 A, r E_Cl = 0.65 A and r E_Br = 0.70 A. From selected sections in ELF data we obtained precise topology and metrics details of these tori. For M* 2 OE 2 {E 3 } 2 family the E twins attached to O have also been localized, their size remaining constant with r E_O = 0.68 A in all studied compounds. The lone pair twins in the series M*F 3 E 2 (M* = Cl, Br, I; M* trivalent oxidation state) as well as in noble gas tetrafluoride XeF 4 E 2 provide remarkable examples: rE evolution versus Z, r E_Cl = 0.77 A (Z = 17), r E_Br = 0.85 A (Z = Br) and r E_I = 0.90 A (Z = 53), follow a linear expansion while in the xenon case with a close Z Xe = 54 but with tetravalent oxidation state, Xe exhibits a radius r E_Xe = 0.95 A, indicating the important influence of the charge magnitude on E volume. The interaction of cations with E centroid: Ec -defined as the electronic volume attached to the lone pair- of neighboring molecules is plausible in explaining unusually short distances between cations. Even surrounded by E torus the cations obviously exert attractive influence through its vortex axis. Based on combined stereochemistry and ab initio topology analyses the paper endeavors showing the unavoidable necessity to accurately account for electron lone pairs: – position of their centroid, – their shape, – their size, – and their deformation (knowing that the electron cloud which accompanies them exhibits a certain plasticity), in order to fully understand their remarkable influence on crystal networks.

中文翻译：

---

卤素间化合物和卤素低价氧化物中电子孤对三联体和孪晶的立体化学和从头算拓扑分析

摘要 本文报告了对几乎没有检查的两类基于 VIIA 的晶体的彻底调查：一方面是卤素间化合物 ClF、ClF 3 、BrF 3 和 IF 3 ，另一方面是卤素低氧化物 F 2 O、Cl 2 O 和 Br 2 O手，以及稀有气体氟化物（此处示例性为 XeF 4 ），都表现出电子（非键合）孤对以双胞胎和三重态形式合并的特殊立体化学。特别是关于众所周知的 VSEPR（价壳电子对排斥）模型，我们提出了合并晶体化学和密度泛函理论（DFT）电子定位函数（ELF）的原始方法，以提供精确的拓扑分析和电子孤对几何的精确度量。在这种情况下，我们通过连接 E 设计孤对 (LP) 和 M* 来设计带 LP 的元素来重写上面的化学式：ClF{E 3 }, M* 2 OE 2 {E 3 } 2 (M* = F , Cl, Br), M*F 3 E 2 (M* = Cl, Br, I) 和 XeF 4 E 2 。然后在 ClF{E 3 } 和 M* 2 OE 2 {E 3 } 2 (M* = F, Cl, Br) 家族中开发了原始立体化学，其中 E 三元组中的 LP 浓度会产生围绕 Cl 和 M* 旋转的电子圆环在大部分带负电的 F 附近，表现出类似阳离子的行为。E 围绕 ClF 中的 Cl，然后围绕所考虑的系列的 M* 呈现椭圆体形状，等效影响半径 (r E ) 随着原子序数 Z 增加，即 r E_F = 0.52 A，r E_Cl = 0.65 A和 r E_Br = 0.70 A。从 ELF 数据中的选定部分，我们获得了这些环的精确拓扑和度量细节。对于 M* 2 OE 2 {E 3 } 2 族，连接到 O 上的 E 双胞胎也被定位，在所有研究的化合物中，它们的大小保持不变，r E_O = 0.68 A。M*F 3 E 2 系列中的孤对双胞胎（M* = Cl、Br、I；M* 三价氧化态）以及稀有气体四氟化物 XeF 4 E 2 提供了显着的例子：rE 演化与 Z、r E_Cl = 0.77 A (Z = 17), r E_Br = 0.85 A (Z = Br) 和 r E_I = 0.90 A (Z = 53)，在氙气情况下遵循线性膨胀，Z Xe = 54 但与在四价氧化态时，Xe 的半径为 r E_Xe = 0.95 A，表明电荷量对 E 体积的重要影响。阳离子与 E 质心的相互作用：Ec - 定义为连接到孤对分子的电子体积 - 在解释阳离子之间异常短的距离时是合理的。即使被 E 环面包围，阳离子也明显通过其涡轴产生有吸引力的影响。基于组合立体化学和 ab initio 拓扑分析，论文努力表明准确解释电子孤对对的不可避免的必要性： – 它们的质心的位置， – 它们的形状， – 它们的大小， – 以及它们的变形（知道伴随着电子云它们表现出一定的可塑性），以充分了解它们对晶体网络的显着影响。即使被 E 环面包围，阳离子也明显通过其涡轴产生有吸引力的影响。基于组合立体化学和 ab initio 拓扑分析，论文努力表明准确解释电子孤对对的不可避免的必要性： – 它们的质心的位置， – 它们的形状， – 它们的大小， – 以及它们的变形（知道伴随着电子云它们表现出一定的可塑性），以充分了解它们对晶体网络的显着影响。即使被 E 环面包围，阳离子也明显通过其涡轴产生有吸引力的影响。基于组合立体化学和 ab initio 拓扑分析，论文努力表明准确解释电子孤对对的不可避免的必要性： – 它们的质心的位置， – 它们的形状， – 它们的大小， – 以及它们的变形（知道伴随着电子云它们表现出一定的可塑性），以充分了解它们对晶体网络的显着影响。