We have studied the crystallographic structure, the oxidation states and the electronic structure of the ternary metal hydride Mg 2 FeH 6 prepared by high-pressure and high-temperature reaction from the simple hydrides. This procedure provides a well-crystallized sample essential to perform Neutron Powder Diffraction (NPD) experiments. By NPD we accessed to subtle crystallographic details of Mg 2 FeH 6 , such as the hydrogen occupancy and the metal-hydrogen distances and angles; a full hydrogen composition with six hydrogen atoms per unit formula is determined. No magnetic structure was observed by NPD at 2 K. The oxidation states of the atoms inside the material and the electronic structure of Mg 2 FeH 6 have been evaluated by x-ray absorption near-edge spectroscopy (XANES). Unexpectedly, the Fe K-edge spectrum shows a zero oxidation state of Fe atoms in agreement with M€ ossbauer data. Our results suggest a metallic nature of the hydride in contrast with the ionic character previously reported for this compound.