Formation of an Fe–H complex anion in YFe 2 : adjustment of imbalanced charge by using additional Li as an electron donor

The novel complex hydride YLiFeH6 with the Fe–H complex anion ([FeH6]4−) was synthesized by hydrogenation of YFe2 together with additional Li. Li adjusts the original imbalanced charge between Y3+ and [FeH6]4− by donating an electron to convert into Li+ during the hydrogenation, resulting in the formation of the well charge-balanced state of Y3+Li+[FeH6]4−.