We present a theoretical investigation on the structural evolution and bonding properties of Pd_nC₂^−/0 (n = 1−7) clusters using density functional theory calculations. The results showed that the two C atoms in Pd₁₋₇C₂^−/0 directly interact with each other to form a C–C bond, except for neutral Pd₆C₂. The Pd atoms can be viewed as an integral cluster unit interacting with C₂ frameworks and have very weak interactions with each other. Interestingly, Pd₆C₂ neutral has a D_3d symmetric bicapped trigonal antiprism structure with the two C atoms located at the apex positions and shows σ plus π double delocalized bonding patterns.

中文翻译：

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Pd _n C _2- ^{/ 0}（n = 1-7）团簇的结构和键合性质

我们使用密度泛函理论计算对Pd _n C _2- ^{/ 0}（n = 1-7）团簇的结构演化和键合性质进行了理论研究。结果表明，除中性Pd ₆ C ₂以外，Pd _1-7 C _2- ^{/ 0}中的两个C原子直接相互作用形成C-C键。Pd原子可以看作是与C ₂骨架相互作用的整体簇单元，并且彼此之间的相互作用非常弱。有趣的是，中性Pd ₆ C ₂具有D _3d 两个C原子位于顶点位置的对称对称三足三角形反棱镜结构，并显示σ加π双离域结合模式。