ChemInform Abstract: A Tale of Two Polymorphs — Growth and Characterization of α‐LnNiGa₄ (Ln: Y, Gd—Yb) and β‐LnNi_1‐xGa₄ (Ln: Tb—Er).

Abstract

A Tale of Two Polymorphs -Growth and Characterization of α-LnNiGa 4 (Ln: Y, Gd-Yb) and β-LnNi1-xGa4 (Ln: Tb-Er). -Single crystals of two polymorphs of LnNiGa4, orthorhombic α-LnNiGa4 (Ln: Y, Gd-Yb) and the new tetragonal β-LnNi0.9Ga4 (Ln: Tb-Ho) polymorphs, and β-ErNi0.8Ga4 are synthesized from the elements by the self-flux method (1423 K, 24 h). The compounds are characterized by XRD, magnetization, and electrical resistivity measurements. The orthorhombic α-phases crystallize isostructurally to YNiAl4 in the space group Cmcm with Z = 4. The structure contains edge-sharing Ni@Ga7Ln2 (Ln: Y, Gd-Yb) polyhedra which are sandwiched between square nets of Ga atoms. The tetragonal β-phases crystallize in the space group I4/mmm with Z = 4. The structure is a distorted variant of the Ce 2 NiGa 10 -type structure with a Ni deficiency and multiple Ga split positions. The β-phases show antiferromagnetic correlations with magnetic transitions occurring below 7 K. -(MENARD, M. C.; DRAKE, B. L.; MCCANDLESS, G. T.; THOMAS, K. R.; HEMBREE, R. D.; HALDOLAARACHCHIGE, N.; DITUSA, J. F.; YOUNG, D. P.; CHAN*, J. Y.; Eur. J. Inorg. Chem. 2011, 26, 3909-3919, http://dx.