Liu Shengfeng, Corbett John D
Ames Laboratory, Iowa State University, Ames, Iowa 50010, USA.
Inorg Chem. 2003 Aug 11;42(16):4898-901. doi: 10.1021/ic030089k.
The title compounds have been synthesized and characterized structurally and through property measurements and electronic structure calculations. Single-crystal X-ray diffraction analyses reveal that the two compounds crystallize in an orthorhombic system, MgCuAl(2) type (Cmcm, Z = 4, a = 4.486(2), 4.491(3) A, b = 10.991(5), 10.990(6) A, c = 8.154(1), 8.140(4) A for SrPdTl(2), and SrPtTl(2), respectively). The structure can be directly derived from that of hexagonal SrTl(2) (CaIn(2) type) in which four-bonded thallium atoms in shared puckered hexagons generate tunnels. The Pd or Pt is encapsulated (with symmetry reduction) on the side of each tunnel within a distorted trigonal prism. Band structure calculations (EHTB) on both SrTl(2) and SrPdTl(2) demonstrate the effects of the conversion, with strong Pd-Tl bonding and appreciable electron transfer from Tl to Pd. Property measurements show that SrPdTl(2) is metallic, as expected.
已合成了标题化合物，并通过结构表征、性质测量和电子结构计算对其进行了研究。单晶X射线衍射分析表明，这两种化合物均结晶于正交晶系，为MgCuAl(2)型（空间群Cmcm，Z = 4，对于SrPdTl(2)，a = 4.486(2)、4.491(3) Å，b = 10.991(5)、10.990(6) Å，c = 8.154(1)、8.140(4) Å；对于SrPtTl(2)，a、b、c值与之相同）。该结构可直接由六方SrTl(2)（CaIn(2)型）的结构推导而来，在六方SrTl(2)中，共享褶皱六边形中的四键铊原子形成了隧道。Pd或Pt（对称性降低）封装在每个隧道侧面的扭曲三角棱柱内。对SrTl(2)和SrPdTl(2)的能带结构计算（EHTB）表明了这种转变的影响，存在较强的Pd - Tl键合以及从Tl到Pd的可观电子转移。性质测量表明，正如预期的那样，SrPdTl(2)是金属性的。
