Molten Ga as a Solvent for Exploratory Synthesis:  The New Ternary Polygallide Sm₂NiGa₁₂

Abstract

Molten Ga is an excellent solvent for the preparation of the polygallide Sm2NiGa12. The compound is metallic and adopts an unusual three-dimensional structure composed of two different kinds of alternating segments. One segment has Ni and Ga atoms and is reminiscent of the KCu4S3 structure type. The other has only Ga atoms and adopts an elaborate Ga network.

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

“…The Ge(1)-and Ge(4)-centered tetrahedra are moderately distorted [90.59(6)±118.11(4)8 for Ge (1), and 100.60(5)±125.86(7)8 for Ge (4)]. The remaining two Ge atoms have grossly distorted environments with angles that range from 58.82(5) to 124.38(4)8 for Ge (2), and from 60.89(6) to 123.55(4)8 for Ge (5). The average Ge À Ge distance in 1 is 2.54 ä; in view of the sum of covalent radii [34] for two Ge atoms (2.44 ä) it can be considered normal.…”

“…The Ga(1)-, Ga(2)-, and Ga(4)-centered tetrahedra are only slightly distorted. The Ge-GaGe angles vary from 102.34(5) to 119.90(7)8 for Ga(1), from 100.81(5) to 127.40(7)8 for Ga (2), and from 102.85(5) to 115.43(4)8 for Ga (4). However, the tetrahedron formed around Ga(3) is strongly compressed; one of the angles is as (5)8.…”

“…We have reported a number of intermetallics grown from Ga flux; these include RENiSi 3 , [1] Sm 2 NiGa 12 , [2] RE 4 FeGa 12Àx Ge x , [3] RE 0.67 M 2 Ga 5 + nÀx Ge x [4] (M = Ni, Co), RE 3 Ga 9 Ge, [5] REMGa 3 Ge (M = Ni, Co), and RE 3 Ni 3 -Ga 8 Ge 3 . [6,7] However, examples of Zintl compounds obtained from molten Ga are relatively scarce and include the clathrate compounds M 8 Ga 16 Tt 30 [8,9] (M = Ba, Sr; Tt = Si, Ge) and the Zintl phase Eu 4 Ga 8 Ge 16 .…”

“…Electrical conductivity and thermopower measurements were performed on single-crystal samples of Yb 3 Ga 4 Ge 6 (2). The almost linear decrease in conductivity with increasing temperature indicates metallic behavior (Figure 9 A).…”

Rare‐Earth Cobalt Gallides RE4Co3Ga16 (RE = Gd–Er, Y): Self‐Interstitial Derivatives of RE2CoGa8

“…It would be worthwhile to target the preparation of hypothetical RE 4 M 3 Ga 16 (M = Rh, Ir) or RE 4 Co 3 In 16 compounds to verify the factors limiting the substitutional range of RE. Analysis of the electronic structure suggests that, as in many other ternary RE-M-Ga phases, [24] electron transfer takes place from RE to both Co and Ga atoms, so that RE 4 Co 3 Ga 16 contains formally anionic Co species as well as a polyanionic Ga-Ga network with weak multicentre bonding. The distortion accompanying the stuffing of Co atoms into RE 2 CoGa 8 tends to be detrimental to the occurrence of interesting physical properties; the magnetic ordering temperatures decrease slightly and no superconducting transition was observed down to ca.…”