All manipulations were conducted in an argon filled glove-box, where a mixture of the elements with the nominal composition 'Eu2.5Cd1.5MnPt2' was loaded in a Ta crucible which was welded-sealed before it is flame sealed in a fused silica tube, and allowed to react at 1000 °C for 12 h and, then slowly cool-down to room temperature over a period of 72 hours. Slight excesses of Eu and Cd in the starting mixture were necessary to compensate their losses by evaporation as well as Eu surface oxidation during the transfer of the sample to the arc-welding system in order to weld-seal the tantalum crucible. The reaction product was analysed by X-ray diffraction methods (powder and single crystal), revealing that it is multiphasic with the quaternary Eu2Mn1-xCd1+xPt2 phase as the main compound and, Eu2O3 as main impurity with others not yet identified minor phases. The product appears to be air-stable after many months of exposure to the atmosphere. Single-crystal diffraction data could be refined using the software package SHELXTL. The most relevant crystallographic data and refinement details are listed in Table and, Table contains the atomic positions and equivalent displacement parameters. The compound crystallizes in the orthorhombic space group Pnma with six independent crystallographic sites (Wyckoff 4c). As listed in Table , two atomic sites were assigned to Eu atoms and two others to Pt atoms, while Mn and Cd mixed occupancy is observed on the two remaining atomic sites, albeit with strong differential site preference, as one of the atomic sites is mainly occupied by Cd2 at 89% (11% Mn2) and the other by mainly Mn1 at 78 % (22% Cd1).