Intermetallics as Zintl Phases: Yb₂Ga₄Ge₆ and RE₃Ga₄Ge₆ (RE=Yb, Eu): Structural Response of a [Ga₄Ge₆]⁴⁻ Framework to Reduction by Two Electrons

Abstract

Two new intermetallic compounds, Yb(2)Ga(4)Ge(6) and Yb(3)Ga(4)Ge(6), were obtained from reactions in molten Ga. A third compound, Eu(3)Ga(4)Ge(6), was produced by direct combination of the elements. The crystal structures of these compounds were studied by single-crystal X-ray diffraction. Yb(2)Ga(4)Ge(6) crystallizes in an orthorhombic cell with a=4.1698(7), b=23.254(4), c=10.7299(18) A in the polar space group Cmc2(1). The structure of RE(3)Ga(4)Ge(6) is monoclinic, space group C2/m, with cell parameters a=23.941(6), b=4.1928(11), c=10.918(3) A, beta=91.426(4) degrees for RE=Yb, and a=24.136(2), b=4.3118(4), c=11.017(1) A, beta=91.683(2) degrees for RE=Eu. The refinement [I>2 sigma(I)] converged to the final residuals R(1)/wR(2)=0.0229/0.0589, 0.0411/0.1114, and 0.0342/0.0786 for Yb(2)Ga(4)Ge(6), Yb(3)Ga(4)Ge(6), and Eu(3)Ga(4)Ge(6), respectively. The structures of these two families of compounds can be described by a Zintl concept of bonding, in which the three-dimensional [Ga(4)Ge(6)](n-) framework serves as a host and electron sink for the electropositive RE atoms. The structural relation of RE(3)Ga(4)Ge(6) to of Yb(2)Ga(4)Ge(6) lies in a monoclinic distortion of the orthorhombic cell of Yb(2)Ga(4)Ge(6) and reduction of the [Ga(4)Ge(6)] network by two electrons per formula unit. The results of theoretical calculations of the electronic structure, electrical transport data, and thermochemical and magnetic measurements are also reported.

Indium Flux-Growth of Eu2AuGe3: A New Germanide with an AlB2 Superstructure

“…The metal flux technique is an excellent tool for exploring novel intermetallic compounds. [15][16][17][18][19][20][21][22][23][24][25] *To whom correspondence should be addressed. E-mail: pottgen@ uni-muenster.de (R.P.…”

Intermetallic Compounds with Near Zintl Phase Behavior: RE2Zn3Ge6 (RE = La, Ce, Pr, Nd) Grown from Liquid Indium

“…These include Sm 2 NiGa 12 , 4 Eu 4 Ga 8 Ge 16 , 5 Ba 8 Ga 16 -Ge 30 , 6 and Yb 3 Ga 6 Ge 4 . 7 This raises the question as to how indium would perform. Indium possesses many of the same qualities that make Al and Ga attractive for exploratory synthesis, namely, its low melting point, its inability to form binaries with Ge or Si, and the solubility of Ge, Si, and a host of transition and lanthanide metals in it.…”

“…The remarkable utility of Al and Ga as solvents to explore new intermetallic phases in the systems RE/TM/Al, RE/TM/Al/Si(Ge), RE/TM/Ga/Si(Ge), RE/TM/Ga, and RE/Ga/Ge (RE is a rare earth metal and TM is a transition metal) has facilitated the discovery of many new and novel materials. These include Sm 2 NiGa 12 , Eu 4 Ga 8 Ge 16 , Ba 8 Ga 16 Ge 30 , and Yb 3 Ga 6 Ge 4 . This raises the question as to how indium would perform.…”

Complex Crystal Chemistry of Yb6(CuGa)50 and Yb6(CuGa)51 Grown at Different Synthetic Conditions

“…[6][7][8][9][10] Structurally, Ybcontaining ternary intermetallic systems contain diverse compounds, which often crystallize in the own, unique, structure types. There have been discoveries of new Yb based interesting compounds in recent past -YbCuGa3, 11 Yb4TGe8, 12 YbMn0.33Si3.67, 13 Yb3AuGe2In3, 14 YbGe2.83, 15 YbGa4Ge2, 16 Yb3Ga4Ge6 17 . This background motivated us to find more new compounds with a particular focus on Yb-Cu-Ga systems as not many compounds reported in this family.…”

“…Generally, the hybridization (interaction) strength among the magnetic 4f electrons and the s, p, and d conduction electrons determines the stability of the different ground states. − Because of the existence of its two energetically similar electronic configurations, Yb-based compounds show intermediate valency, strong electron correlation, heavy fermion superconductivity, Kondo lattice behavior, and antiferromagnetic behavior. − Structurally, Yb-containing ternary intermetallic systems contain diverse compounds, which often crystallize in their own, unique, structure types. There have been discoveries of new Yb-based interesting compounds in recent pastYbCuGa 3 , Yb 4 T Ge 8 , YbMn 0.33 Si 3.67 , Yb 3 AuGe 2 In 3 , YbGe 2.83 , YbGa 4 Ge 2 , Yb 3 Ga 4 Ge 6 . This background motivated us to find more new compounds with a particular focus on Yb–Cu–Ga systems, as not many compounds are reported in this family.…”