Electron diffraction of samples of the alloy Pr-77 at.% Fe, preliminarily annealed for 100 hat 600°C, revealed the following phases: $\alpha-Pr$, $Pr_2Fe_{17}$, $PrFe_2 (С14)$, and $PrFe_2 (С15)$. The lattice parameters were determined for the hitherto unobserved intermetallic compounds $PrFe_2$ of two types: (i) $MgZn_2 (С14)$, space group $P6_3/mmc$, $а = 5,26 А$, $с = 8,62 А$ and (ii) $MgCu_2 (C15)$, space group $Fd3m$, $а = 6,76 А$. Structural-orientation correlations between these compounds and $Pr_2Fe_{17}$ were established, which shows that the three compounds can be transformed into each other.
$^1$Department of Solid-State Physics, Faculty of Physics, Moscow State University, Leninskie Gory, Moscow, 119992, Russia
$^2$A.A. Baikov Institute of Metallurgy, Academy of Sciences of the Russian Federation
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