Quaternary alumogermanides
in the Er-{Co,Ni}-Al-Ge systems
Chem.
Met. Alloys 1
(2008) 254-260
https://doi.org/10.30970/cma1.0056
Grygorii DEMCHENKO, Joanna KOŃCZYK, Pavlo DEMCHENKO, Roman GLADYSHEVSKII,
Wiesław MAJZNER, Liliya MURATOVA
The crystal structures of two new quaternary alumogermanides have been determined from X-ray single
crystal and powder diffraction data. Er2CoAl4Ge2
crystallizes with a Tb2NiAl4Ge2-type
structure: space group I4/mmm, Pearson symbol tI18, cell parameters a =
4.0970(6), c = 19.343(4) Å, R1 =
0.0492, wR2 = 0.1195, Goof = 1.115,
whereas the structure of ErNiAl4Ge2 adopts the YNiAl4Ge2
type: space group R-3m,
Pearson symbol hR24, cell parameters a = 4.07160(8), c = 30.7027(9) Å, Rp =
0.0550, Rwp
= 0.0708, RB = 0.0523, RF = 0.0402, c2 = 3.88. The structures
are ordered and built up from structural slabs characteristic of binary and
ternary compounds via intergrowth.
Environment of the Ni atoms in the structure of
ErNiAl4Ge2: presentation as a deformed cube (left) and
Al2 atoms in cyclohexane chair conformation (right).
Keywords
Rare-earth alumogermanides
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