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Ternary Laves phases Sc 0.22(1) Ta 0.78(1) Fe 2 and Sc 0.63(1) In 0.37(1) Co 2 – coloring variants of the MgZn 2 and MgNi 2 type
Author(s) -
Gulay Nataliya L.,
Kalychak Ya. M.,
Pöttgen Rainer
Publication year - 2021
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.202000362
Subject(s) - crystallography , laves phase , ternary operation , crystal structure , materials science , powder diffraction , diffraction , type (biology) , solid solution , x ray crystallography , chemistry , intermetallic , metallurgy , physics , alloy , ecology , computer science , biology , programming language , optics
The ternary Laves phases Sc 0.22(1) Ta 0.78(1) Fe 2 and Sc 0.63(1) In 0.37(1) Co 2 were synthesized by arc‐melting appropriate amounts of the binary phases ScFe 2 and TaFe 2 or Sc, In and Co, respectively. The samples were studied by powder X‐ray diffraction and the structures were refined from single crystal X‐ray diffraction data: P 6 3 / mmc , a =484.96(7), c =793.17(11) pm, wR 2=0.0604, 147 F 2 values, 12 variables for Sc 0.22(1) Ta 0.78(1) Fe 2 and P 6 3 mc , a =488.61(4), c =1599.54(12) pm, wR 2=0.0389, 553 F 2 values, 35 variables for Sc 0.63(1) In 0.37(1) Co 2 . Sc 0.22(1) Ta 0.78(1) Fe 2 derives from the MgZn 2 type having a mixed Sc/Ta occupancy on the 4 f magnesium position. Sc 0.63(1) In 0.37(1) Co 2 crystallizes with a new structure type which derives from the Laves phase MgNi 2 . A translationengleiche symmetry reduction leads to the non‐centrosymmetric space group P 6 3 mc which allows partial Sc/In ordering with different Sc/In ratios on four crystallographically independent sites. While ScFe 2 and TaFe 2 build a complete solid solution Sc 1–x Ta x Fe 2 with MgZn 2 type structure, we observe a switch in structure type for Sc 1–x In x Co 2 from the cubic MgCu 2 type (x=0–0.22) to the non‐centrosymmetric derivative from MgNi 2 at x=0.37.