M-F interatomic distances and effective volumes of second and third transition series MF6- and MF6(2-) anions.
M-F interatomic distances and effective volumes of second and third transition series MF6- and MF6(2-) anions.
复制标题
第二和第三过渡系列 MF6- 和 MF6(2-) 阴离子的 M-F 原子间距离和有效体积。
作者：
Oliver Graudejus;A. Wilkinson;Lisa C. Chacón;Neil Bartlett
第二和第三过渡系列的代表性 LiMF6 和 Li2MF6 盐的同步加速器 X 射线粉末衍射数据 (SPDD) 提供了晶胞参数，并根据 Rietveld 分析提供了 M-F 原子间距离。通过 LiOsF6、Li2PtF6 和 KRhF6 的 X 射线单晶结构分析也获得了 M-F 距离。 LiMF6均具有LiSbF6结构类型（空间群R3）。对于 M = Ta 到 Au，原始晶胞体积随着核电荷 (Z) 的增加而减小，体积 (sigma = 0.01 A3) 如下：Ta, 111.26；奥斯，102.42；红外线，100.77；铂，99.62；和金，99.12 A3。随着 Z 的增加，从 Nb 到 Rh 发生类似的收缩，原始细胞体积 (sigma = 0.01 A3) 为：Nb，110.92；茹，100.51；和Rh，98.64 A3。对于 TaF6- 到 AuF6-，整个系列的 M-F 距离没有显着差异，约为 1.87(1) A；另外，Nb-F、Ru-F 和 Rh-F = 1.86(1) A。在每个系列中，LiMF6 结构（沿 c 堆叠的单独的 MF6- 层和 Li+ 层）的六方晶胞表示的 a 和 c 值平滑变化。随着 Z 的增加，a 减少，c 增加。 a 的变化与体积变化一样，表明 MF6- 的尺寸随 Z 减小。c 的变化表明 F-配体上的电荷随 Z 减小。在三金红石 Li2MF6 系列中，M = Mo 至 Pd，分子式单元体积随 Z 减小(Mo, 100.92(6); Ru, 98.21(1); Rh, 97.43(1); Pd, 96.83(1) A3) 并且 M-F 发生缩短 (Mo-F = 1.936(4); Ru-F = 1.921(7); Rh-F = 1.910(7); Pd-F = 1.899(4) A）。第三个过渡系列的 MF6(2-) 盐的不太丰富的数据表明了类似的趋势。对于这两个系列，MF6(2-) 的 M-F 距离比 MF6- 长 0.03-0.09 A。
Synchrotron X-ray powder diffraction data (SPDD) for representative LiMF6 and Li2MF6 salts of the second and third transition series have provided unit-cell parameters and, from Rietveld analysis, M-F interatomic distances. M-F distances have also been obtained from X-ray single-crystal structural analyses of LiOsF6, Li2PtF6, and KRhF6. The LiMF6 all have the LiSbF6 structure type (space group R3). For M = Ta to Au the primitive unit cell volume decreases with increasing nuclear charge (Z), the volumes (sigma = 0.01 A3) being as follows: Ta, 111.26; Os, 102.42; Ir, 100.77; Pt, 99.62; and Au, 99.12 A3. A similar contraction, with increase in Z, occurs from Nb to Rh, the primitive cell volume (sigma = 0.01 A3) being: Nb, 110.92; Ru, 100.51; and Rh, 98.64 A3. For the TaF6- to AuF6- the M-F distances are not significantly different across the series, at approximately 1.87(1) A; also, Nb-F, Ru-F, and Rh-F = 1.86(1) A. In each series, the a and c values of the hexagonal-cell representation for the LiMF6 structure (separate layers of MF6- and Li+ stacked along c) change smoothly. As Z increases, a decreases and c increases. The variation in a, like the volume change, indicates that the size of MF6- is decreasing with Z. The variation in c suggests that the charge on the F-ligand is decreasing with Z. In the trirutile Li2MF6 series, M = Mo to Pd, the formula-unit volume decreases with Z(Mo, 100.92(6); Ru, 98.21(1); Rh, 97.43(1); Pd, 96.83(1) A3) and a shortening in M-F occurs (Mo-F = 1.936(4); Ru-F = 1.921(7); Rh-F = 1.910(7); Pd-F = 1.899(4) A). The less abundant data for MF6(2-) salts of the third transition series indicate similar trends. For both series, M-F distances of MF6(2-) are longer by 0.03-0.09 A than in MF6-.