Crystal structure of the ternary compound Dy₃Ga_2.54Sn_2.46

Chem. Met. Alloys 5 (2012) 160-165

https://doi.org/10.30970/cma5.0225

Vitaliia FEDYNA, Yaroslav TOKAYCHUK, Roman GLADYSHEVSKII

The crystal structure of the new ternary compound Dy₃Ga_2.54(5)Sn_2.46(5) belongs to the Pu₃Pd₅ structure type (Pearson symbol oS32, space group Cmcm, a = 9.7300(3), b = 7.7081(2), c = 9.7925(3) Å). The atoms of the p-elements are distributed over three Wyckoff positions with a tendency towards ordering: two sites for Ga and one site for Sn (ideal composition Dy₃Ga₃Sn₂). They form isolated empty square-pyramidal clusters. The structure can also be decomposed into two kinds of layer. At z ≈ 0 and z ≈ ½ Dy (site Dy1) and Ga (site M2 = 0.81(3)Ga2 + 0.19(3)Sn2) atoms form slightly puckered deformed NaCl-type layers. At z = ¼ and z = ¾ Dy (site Dy2), Ga (M3 = 0.74(3)Ga3 + 0.26(3)Sn3) and Sn (M1 = 0.09(4)Ga1 + 0.91(4)Sn1) atoms form flat deformed LiFeO₂-type layers (the LiFeO₂ type is a ternary ordered derivative of the binary NaCl type). The structure type Pu₃Pd₅ belongs to the family of deformation variants of the structure type Rh₅Ge₃.

Content of the unit cell and square pyramidal arachno-type clusters in the structure of Dy₃Ga_2.54Sn_2.46.

Keywords

Dysprosium / Gallium / Tin / Intermetallic compound / X-ray powder diffraction / Crystal structure