Experimental determination of hydrogen positions in Im-3m Mg4Pt3H6

Determine the hydrogen atomic positions in the Im-3m Mg4Pt3H6 crystal structure, which could not be resolved using x-ray diffraction in this study, to establish the precise locations of hydrogen within the linear [PtH2]2− complexes and quantify Pt–H bond lengths under relevant pressures.

Background

The paper reports the prediction and successful synthesis of Mg4Pt3H6 in the Im-3m space group, featuring Mg2+ cations and linear [PtH2]2− complexes. Structural validation was carried out using synchrotron x-ray diffraction and Rietveld refinement.

Due to the weak x-ray scattering of hydrogen, the authors could not directly determine the hydrogen atomic positions and instead relied on calculated positions to estimate Pt–H bond distances. An experimental determination of hydrogen positions remains unresolved and is important for fully validating the structural model and for accurate property calculations.