Interaction of yttrium with nickel and phosphorus: Phase diagram and structural chemistry

The interaction between the components of the ternary Y–Ni–P system has been investigated by means of electron probe microanalysis, X-ray phase and structure analyses, and the isothermal section of the phase diagram at 1070K has been constructed for the first time. Existence of the earlier reported eight ternary phosphides of yttrium and nickel was confirmed, among them seven ternaries are daltonide compounds: YNi4P2 (ZrFe4Si2-type structure), Y2Ni12P7 (Zr2Fe12P7-type structure), Y6Ni20P13 (Zr6Ni20P13-type structure), Y6Ni14.9P10.18 (own structure type), Y20Ni42P30.34 (Sm20Ni41.6P30-type structure), Y15Ni28P21 (Tb15Ni28P21-type structure), and YNiP (Tb1−xNiP-type structure), whereas YNi1.66−1.78P2 (ThCr2Si2-type structure) is a berthollide compound with small homogeneity range. The crystal structures of the some ternary phosphides have been determined by X-ray powder diffraction (YNi4P2 and YNi1.66−1.78P2) and single crystal diffraction (Y2Ni12P7) techniques. Structure block with the composition Ln10M21X15 of the homologous series of the compounds (Ln,M)~2X. [Display omitted] •The phase diagram of Y–Ni–P at 1070K has been constructed.•Existence of the eight ternary phosphides of yttrium and nickel has been confirmed.•The crystal structures of YNi4P2 and YNi1.66-1.78P2 have been determined by powder X-ray diffraction.•The crystal structure of Y2Ni12P7 has been established by single crystal diffraction.