ChemInform Abstract: Vacancy Ordering as a Driving Factor for Structural Changes in Ternary Germanides: The New R₂Zn_1‐xGe₆ Series of Polar Intermetallics (R: Rare‐Earth Metal).

Abstract

Metal).-The new compounds Ln 2Zn1-xGe6 (Ln: La-Nd, Sm, Gd-Ho) are prepared from the elements (Ta crucible, 950 C) and characterized by single crystal XRD. With light rare earth metals up to Tb, the compounds crystallize in the orthorhombic space group Cmce with Z = 8 (Ce 2(Ga0.1Ge0.9)7-type structure), whereas the Dy compound crystallizes with a new structure type in the monoclinic space group P2 1/m, and Z = 4. The Zn deficiency increases along the series and is the key factor governing structural changes. TB-LMTO-ASA electronic structure calculations on La2ZnGe6 confirm the presence of infinite covalent Ge zigzag chains and three-bonded corrugated layers connected via Zn atoms to form a polyanionic network stabilized by La atoms. -(SOLOKHA*, P.; DE NEGRI, S.; PROSERPIO, D. M.; BLATOV, V. A.; SACCONE, A.; Inorg. Chem. 54 (2015) 5, 2411-2424, http://dx.doi.org/10.1021/ic5030313 ; Dip. Chim. Chim. Ind.,