Hibble Simon J, Hannon Alex C, Cheyne Simon M
School of Chemistry, University of Reading, Reading RG6 6AD, UK.
Inorg Chem. 2003 Jul 28;42(15):4724-30. doi: 10.1021/ic0342043.
The structure of gold cyanide, AuCN, has been determined at 10 and 300 K using total neutron diffraction. The structure consists of infinite [bond]Aubond[bond]Aubond[bond] linear chains, hexagonally packed, with the gold atoms in sheets. The Au-C and Au-N bond lengths are found to be identical, with d(Au(-C/N) = 1.9703(5) A at 300 K. This work supersedes a previous study, by others, which used Rietveld analysis of neutron Bragg diffraction in isolation, and found these bonds to have significantly different lengths (Delta d = 0.24 A) at 300 K. The total correlation function, T(r), at 10 and 300 K, has been modeled using information derived from total diffraction. The broadening of inter- and intrachain correlations differs markedly due to random displacements of the chains in the direction of the chain axes. This is a consequence of the relatively weak bonding between the chains. An explanation for the negative thermal expansion in the c-direction, which occurs between 10 and 300 K, is presented.
已利用全中子衍射在10 K和300 K下测定了氰化金（AuCN）的结构。该结构由无限的[键]Au键[键]Au键[键]线性链组成，呈六方堆积，金原子位于片层中。发现Au-C键长和Au-N键长相同，在300 K时d(Au(-C/N)) = 1.9703(5) Å。这项工作取代了其他人之前的一项研究，该研究单独使用中子布拉格衍射的Rietveld分析，发现在300 K时这些键的长度有显著差异（Δd = 0.24 Å）。已利用从全衍射获得的信息对10 K和300 K下的总相关函数T(r)进行了建模。由于链在链轴方向上的随机位移，链间和链内相关性的展宽有明显差异。这是链间相对较弱键合的结果。给出了在10 K至300 K之间c方向出现负热膨胀的解释。
