Synthesis and crystal structure of new compounds from the Y–Mg–Ni system

The synthesis, structural characterization, and chemical bonding peculiarities of new intermetallic compounds from Y–Mg–Ni ternary system are reported herein. The crystal structures of these compounds were determined by single-crystal and X-ray powder diffraction analysis. Three ternary compounds were studied: Y2Mg11Ni2 [own structure type, monoclinic, Pearson Symbol mS30, Space Group C2/m, a=18.969(4), b=3.6582(7), c=11.845(2) Å, β=125.07(3)°], Y4Mg3Ni2 [Ru4Al3B2 structure type, tetragonal, P4/mmm, tP18, a=10.8668(2), c=3.59781(12) Å] and YMgNi [MoAlB structure type, orthorhombic, Cmcm, a=3.6713(4), b=17.708(3), c=3.9583(5) Å]. New compositions of Y1−xMgxNi4 and Y5−xMg24+x solid solutions were detected: YMg0.86(1)Ni4.14(1) [SnMgCu4 structure type, cubic, F4̅3m, cF24, a=7.0747(6) Å] and Y4.28(1)Mg24.72(1) [Ti5Re24 structure type, cubic, I4̅3m, cI58, a=11.2655(11) Å]. The crystal structure peculiarities of these compounds are discussed. A particular attention has been given to Y2Mg11Ni2 and its relations with other Mg-containing compounds. Crystallographic analysis together with linear muffin-tin orbital band structure calculations reveals the presence of [Y2Ni4@Mg20] and [Y4Ni2@Mg18] clusters in Y2Mg11Ni2 phase. For Y4Mg3Ni2 the formation of the Ni–Mg nets was observed, while the Y atoms form a monolayer.