The alkaline earth-palladium-germanides Sr3Pd4Ge4 and BaPdGe.

The germanides Sr₃Pd₄Ge₄ and BaPdGe were obtained from high-temperature reactions in sealed niobium ampoules and their structures have been determined from single-crystal X-ray diffraction data: <italic>a</italic>=444.2(1), <italic>b</italic>=438.1(1), <italic>c</italic>=2472.2(7) pm, space group <italic>Immm</italic>, U₃Ni₄Si₄ type, <italic>wR</italic>2=0.0471, 576 unique reflections, 25 parameters for Sr₃Pd₄Ge₄ and <italic>a</italic>=677.09(8), space group <italic>P</italic>2₁3, LaIrSi type, <italic>wR</italic>2=0.0322, 409 unique reflections, nine parameters for BaPdGe. Both germanides have pronounced three-dimensional [Pd₄Ge₄]^{<italic>δ</italic>−} and [PdGe]^{<italic>δ</italic>−} polyanionic networks with Pd–Ge bonding interactions. This is confirmed by the density functional theory (DFT)-based electronic structure investigations, the trends of charge transfer and crystal orbital overlap population (COOP) analyses. [ABSTRACT FROM AUTHOR]