Ptashkina Evgeniya A, Kabanova Elizaveta G, Tursina Anna I, Yatsenko Alexandr V, Kuznetsov Victor N
Department of Chemistry, Moscow State University, 119991 Moscow, Russian Federation.
Acta Crystallogr C Struct Chem. 2018 Mar 1;74(Pt 3):295-299. doi: 10.1107/S2053229618001973. Epub 2018 Feb 14.
A new CuAu-type ternary phase (τ phase) is found in the AuPd-rich part of the Au-In-Pd system. It has a broad homogeneity range based on extensive (Pd,Au) and (In,Au) replacement, with the composition varying between AuInPd and AuInPd. The occupancies of the crystallographic positions were studied by single-crystal X-ray diffraction for three samples of different composition. The sites with m-3m symmetry are occupied by atoms with a smaller scattering power than the atoms located on 4/mmm sites. Two extreme structure models were refined. Within the first, the occupation type changes from (Au,In,Pd)(Pd,In) to (Au,Pd)(In,Pd,Au) with an increase in the Au gross content. For the second model, the occupation type (Au,In,Pd)(Pd,Au) remains essentially unchanged for all Au concentrations. Although the diffraction data do not allow the choice of one of these models, the latter model, where Au substitutes In on 4/mmm sites, seems to be preferable, since it agrees with the fact that the homogeneity range of the τ phase is inclined to the Au corner and provides the same occupation type for all the studied samples of different compositions.
在Au-In-Pd体系富AuPd部分发现了一种新的CuAu型三元相（τ相）。基于广泛的（Pd,Au）和（In,Au）替代，它具有较宽的均匀性范围，其组成在AuInPd和AuInPd之间变化。通过单晶X射线衍射对三个不同组成的样品研究了晶体学位置的占有率。具有m-3m对称性的位点被散射能力比位于4/mmm位点上的原子小的原子占据。对两个极端结构模型进行了精修。在第一个模型中，随着Au总含量的增加，占据类型从（Au,In,Pd）（Pd,In）变为（Au,Pd）（In,Pd,Au）。对于第二个模型，对于所有Au浓度，占据类型（Au,In,Pd）（Pd,Au）基本保持不变。尽管衍射数据无法在这些模型中做出选择，但后一个模型，即Au在4/mmm位点上替代In的模型，似乎更可取，因为它与τ相的均匀性范围倾向于Au角这一事实相符，并且为所有不同组成的研究样品提供了相同的占据类型。
