Department of Chemistry, Iowa State University, Ames, Iowa 50011, USA.
Inorg Chem. 2011 Mar 7;50(5):1808-15. doi: 10.1021/ic102243c. Epub 2011 Jan 21.
A novel hexagonal phase discovered near the Ca(15)Au(60)Sn(25) quasicrystal and its cubic approximants (ACs) was synthesized by means of high-temperature solid-state reactions. Single-crystal structural analyses show that this is a Gd(14)Ag(51) isotype with composition within the range Ca(14)Au(45.56(4)-46.67(4))Sn(5.14(3)-4.14(3)), space group P6/m (No. 175), and lattice parameters a = 12.763(3)-12.879(3) Å and c = 9.326(3)-9.3815(4) Å. In this phase, Sn mixes with Au in two of seven anionic sites to give a strong coloring that generates a narrow honeycomb-like Au/Sn template, in which sizable columns of hexagonal Au stars are confined. This phase transforms into the cubic 2/1 AC phase through a peritectic reaction at ∼678 °C. The valence electron count per atom (e/a) of the present phase is in the range 1.41-1.45. However, it does not appear to follow a Hume-Rothery mechanism.
在 Ca(15)Au(60)Sn(25) 准晶及其立方近晶相 (AC) 附近发现了一种新的六方相，通过高温固相反应合成。单晶结构分析表明，这是一种 Gd(14)Ag(51) 同型物，组成在 Ca(14)Au(45.56(4)-46.67(4))Sn(5.14(3)-4.14(3))范围内，空间群为 P6/m（No.175），晶格参数 a = 12.763(3)-12.879(3) Å 和 c = 9.326(3)-9.3815(4) Å。在这个相中，Sn 与 Au 在七个阴离子位置中的两个位置混合，导致强烈的着色，产生一个狭窄的蜂窝状 Au/Sn 模板，其中六边形的 Au 星被限制在其中。该相通过在约 678°C 的包晶反应转变为立方 2/1 AC 相。本相的每个原子的价电子数 (e/a) 在 1.41-1.45 范围内。然而，它似乎不遵循 Hume-Rothery 机制。
