Large hydrogen capacity in hydrides R2Ni2In-H (RÂ =Â La, Ce, Pr, Nd) with new structure type

Several new hydrides with the composition R2Ni2InHx (R = La, Ce, Pr, Nd; x ≈ 4.5-5.0) were synthesized. They are based on the R2Ni2In compounds crystallizing in the Mo2FeB2 structure type. So as to accommodate high amount of H atoms (x can theoretically reach the value of 6), the structure changes to orthorhombic, space group Pbam, while the unit-cell volume increases by 10-20%. Nd2Ni2In was found antiferromagnetic, with a first-order magnetic phase transition at TN = 8 K. Applied magnetic field μ0H < 0.3 T induces ferromagnetism. TN of Nd2Ni2InH4.5, which is a more regular antiferromagnet, is reduced to 5 K.