Centre for Theoretical Chemistry and Physics, The New Zealand Institute for Advanced Study, Massey University Albany, Private Bag 102904, North Shore City, 0745 Auckland, New Zealand.
J Phys Chem A. 2009 Nov 12;113(45):12427-32. doi: 10.1021/jp9025915.
The solid-state structure of mercury oxide and its low-pressure modifications are known to significantly differ from those found for the corresponding zinc and cadmium compounds, that is, one changes from a simple hexagonal wurtzite or cubic rock salt structure found in zinc oxide and cadmium oxide to unusual chainlike montroydite and cinnabar structures in mercury oxide. Here, we present relativistic and nonrelativistic density functional studies which demonstrate that this marked structural difference is caused by relativistic effects. For HgO, the simple rock salt structure is only accessible at higher pressures. Relativistic effects reduce the cohesive energy by 2.2 eV per HgO unit and decrease the density of the crystal by 14% due to a change in the crystal symmetry. Band structure and density of states calculations also reveal large changes in the electronic structure due to relativistic effects, and we argue that the unusual yellow to red color of HgO is a relativistic effect as well.
已知氧化汞的固态结构及其低压变体与相应的锌和镉化合物的结构有显著差异，即从氧化锌和氧化镉中发现的简单六方纤锌矿或立方岩盐结构变为氧化汞中的不寻常链状辉铜矿和辰砂结构。在这里，我们进行了相对论和非相对论密度泛函研究，证明这种显著的结构差异是由相对论效应引起的。对于 HgO，简单的岩盐结构仅在较高压力下才能获得。相对论效应使每个 HgO 单元的内聚能降低 2.2 eV，并由于晶体对称性的改变，使晶体密度降低 14%。能带结构和态密度计算也表明，由于相对论效应，电子结构发生了很大变化，我们认为 HgO 的异常黄色到红色也是相对论效应的结果。
