The Prolific Ternary System Pt/Sn/Nd: Insertion of Pt into the Structures of Sn/Nd Intermetallics Yields Structural Complexity and Wealth.

The understanding of structure and bonding in intermetallic phases still lags behind that of molecular compounds. For that reason, exploring intermetallic phases and identifying structural patterns and relationships are particularly important for closing this knowledge gap. In particular, here we report on the addition of increasing amounts of platinum to ∼2:1 mixtures of tin and neodymium, which yields eight ternary Pt/Sn/Nd compounds, four of which have not been reported before. Interestingly, except for PtSnNd ( 1 ), all observed ternary phases of the system can be derived from the binary compounds Sn 2 Nd and Sn 5 Nd 2 by adding Pt to the composition(s), as they lie on or close to two lines: Sn 2 Nd-Pt (Pt 0.21(1) Sn 2 Nd ( 2 ), PtSn 2 Nd ( 3 ), Pt 1.33 Sn 2 Nd ( 4 ), Pt 2- x Sn 2+ x Nd ( x = 0.27(3), 5 ), and Pt 3 Sn 2 Nd ( 6 )) or Sn 5 Nd 2 -Pt (Pt 1.5 Sn 5- x Nd 2 ( x = 0.16(2), 7 ) and Pt 3 Sn 5 Nd 2- x ( x = 0.161(8), 8 )). While the introduction of increasing amounts of Pt to the binaries Sn 2 Nd and Sn 5 Nd 2 leads to stepwise changes in the coordination environment of Nd, Pt preserves its coordination over the entire system in the form of interpenetrating bipyramidal {PtSn 5 Nd 5 } clusters.