Gougeon Patrick, Al Orabi Rabih Al Rahal, Gautier Régis, Potel Michel
Sciences Chimiques de Rennes, CSM-INSA, UMR CNRS No. 6226, Université de Rennes I, Avenue du Général Leclerc, 35042 Rennes CEDEX, France.
Acta Crystallogr C. 2012 May;68(Pt 5):i25-8. doi: 10.1107/S0108270112016605. Epub 2012 Apr 25.
The structure of scandium dirubidium pentadecamolybdenum nonadecasulfide, Sc(0.43(2))Rb(2)Mo(15)S(19), constitutes a partially Sc-filled variant of Rb(2)Mo(15)S(19) [Picard, Saillard, Gougeon, Noel & Potel (2000), J. Solid State Chem. 155, 417-426]. In the two compounds, which both crystallize in the R ̅3c space group, the structural motif is characterized by a mixture of Mo(6)S(i)(8)S(a)(6) and Mo(9)S(i)(11)S(a)(6) cluster units (i' is inner and a' is apical) in a 1:1 ratio. The two components are interconnected through interunit Mo-S bonds. The cluster units are centred at Wyckoff positions 6b and 6a (point-group symmetries ̅3. and 32, respectively). The Rb(+) cations occupy large voids between the different cluster units. The Rb and the two inner S atoms lie on sites with 3. symmetry (Wyckoff site 12c), and the Mo and S atoms of the median plane of the Mo(9)S(11)S(6) cluster unit lie on sites with .2 symmetry (Wyckoff site 18e). A unique feature of the structure is a partially filled octahedral Sc site with ̅1 symmetry. Extended Hückel tight-binding calculations provide an understanding of the variation in the Mo-Mo distances within the Mo clusters induced by the increase in the cationic charge transfer due to the insertion of Sc.
钪二铷十五钼十九硫化物Sc(0.43(2))Rb(2)Mo(15)S(19)的结构构成了Rb(2)Mo(15)S(19)的部分Sc填充变体[皮卡德、赛拉尔、古热翁、诺埃尔和波泰尔（2000年），《固态化学杂志》155，417 - 426]。在这两种均结晶于R ̅3c空间群的化合物中，结构基序的特征是Mo(6)S(i)(8)S(a)(6)和Mo(9)S(i)(11)S(a)(6)簇单元（“i”为内部，“a”为顶端）以1:1比例混合。这两个组分通过单元间的Mo - S键相互连接。簇单元位于Wyckoff位置6b和6a（点群对称分别为 ̅3.和32）。Rb(+)阳离子占据不同簇单元之间的大空隙。Rb和两个内部S原子位于具有3.对称性的位置（Wyckoff位点12c），并且Mo(9)S(11)S(6)簇单元中间平面的Mo和S原子位于具有.2对称性的位置（Wyckoff位点18e）。该结构的一个独特特征是具有 ̅1对称性的部分填充八面体Sc位点。扩展休克尔紧束缚计算有助于理解由于Sc的插入导致阳离子电荷转移增加而引起的Mo簇内Mo - Mo距离的变化。
