Synthesis of Lanthanoid Nickel-Phosphides Using Sm, Gd, and Dy

• Claire Cassino, Chemistry, University of Delaware

• Svilen Bobev, Department of Chemistry and Biochemistry, University of Delaware

Lanthanoid nickel-phosphides are not well reported; the further one progresses into the lanthanoid series the fewer structures are recorded in the Inorganic Crystal Structure Database (ICSD).  In an effort to supplement these materials, synthesis of unreported ratios of samarium, gadolinium, and dysprosium was attempted. A ratio of each rare earth was reacted for a week in vacuum sealed quartz tubes with nickel and phosphorus. Elemental tin, in ratio of five or greater to the lanthanoid, was used as a flux to promote crystal growth. Analysis of the product was conducted via powder X-ray diffraction and single crystal X-ray diffraction. Samarium in a 1:5:3 ratio reacted to form Sm2Ni12P7, likely due to the flux reacting with some of the nickel and phosphorus to form Ni2SnP. Dysprosium in a 1:5:3 ratio reacted with neither nickel nor phosphorus, unsurprising considering its low reactivity.

It was determined that lanthanoids further in the series do not react under the same conditions as earlier lanthanoids. Different methodology would be required for the successful formation of their nickel-phosphides. Using previous methodology as a baseline, gadolinium and samarium should be reacted with nickel and phosphorus by varying a singular condition until a suitable method may be found. Ongoing work is aimed at continuing to add new lanthanoid nickel-phosphides to the ICSD to allow a better understanding of rare earth metals.