R2-xTi3+xGe4
compounds in the R–Ti–Ge (R = Gd-Lu) systems
Chem.
Met. Alloys 11 (2018) 14-17
https://doi.org/10.30970/cma11.0378
Bogdana BACHYNSKA,
Nataliya MUTS, Khrystyna MILIYANCHUK, Roman GLADYSHEVSKII
The existence of five R2-xTi3+xGe4 compounds (R = Gd, Tb, Dy, Ho, Er) was confirmed at 600°C
and two new compounds, Tm1.79(2)Ti3.21(2)Ge4 and Lu1.74(2)Ti3.26(2)Ge4,
were found. No ~R2Ti3Ge4
compound was observed for Yb. All the
compounds crystallize with partly ordered variants of the structure type Sm5Ge4
(Pearson symbol oP36, space group Pnma).
On going from gadolinium to lutetium, the unit-cell parameters are reduced, due
to the lanthanide contraction, but also due to the fact that the refined
composition becomes richer in Ti. One of the metal-atom sites located between
the structural slabs was found to be fully occupied by titanium, whereas the
other one is mainly or fully occupied by the rare-earth metal. The site located
inside the slabs (rhombic dodecahedral coordination) is preferentially occupied
by Ti.
Rhombic dodecahedron surrounding
site M3 in the R2-xTi3+xGe4 compounds.
Keywords
Rare-earth
metals / Titanium / Germanides / Crystal structure