Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Str. 4, 35032, Marburg, Germany.
Department of Chemistry and Materials Science, Aalto University, 00076, Aalto, Finland.
Chemistry. 2019 Mar 1;25(13):3310-3317. doi: 10.1002/chem.201805298. Epub 2019 Feb 6.
The crystal structures of α-F and β-F have been reinvestigated using neutron powder diffraction. For the low-temperature phase α-F , which is stable below circa 45.6 K, the monoclinic space group C2/c with lattice parameters a=5.4780(12), b=3.2701(7), c=7.2651(17) Å, β=102.088(18)°, V=127.26(5) Å , mS8, Z=4 at 10 K can now be confirmed. The structure model was significantly improved, allowed for the anisotropic refinement of the F atom, and an F-F bond length of 1.404(12) Å was obtained, which is in excellent agreement with spectroscopic data and high-level quantum chemical predictions. The high-temperature phase β-F , stable between circa 45.6 K and the melting point of 53.53 K, crystallizes in the cubic primitive space group Pm n with the lattice parameter a=6.5314(15) Å, V=278.62(11) Å , cP16, Z=8, at 48 K. β-F is isotypic to γ-O and δ-N . The centres of gravity of the F molecules are arranged like the atoms in the Cr Si structure type.
使用中子粉末衍射法重新研究了 α-F 和 β-F 的晶体结构。对于低温相 α-F，其在约 45.6 K 以下稳定，现在可以确认其具有单斜空间群 C2/c，晶格参数为 a=5.4780(12)，b=3.2701(7)，c=7.2651(17)Å，β=102.088(18)°，V=127.26(5)Å，mS8，Z=4，在 10 K 下。结构模型得到了显著改进，允许对 F 原子进行各向异性细化，并得到了 1.404(12)Å 的 F-F 键长，与光谱数据和高水平量子化学预测非常吻合。高温相 β-F，在约 45.6 K 和 53.53 K 的熔点之间稳定，在立方原始空间群 Pm n 中结晶，晶格参数为 a=6.5314(15)Å，V=278.62(11)Å，cP16，Z=8，在 48 K。β-F 与 γ-O 和 δ-N 同型。F 分子的重心像 Cr Si 结构类型中的原子一样排列。
