Eleven new compounds in the RE–Cd–Ge systems (RE=Pr, Nd, Sm, Gd–Yb; Y): Crystal chemistry of the RE2CdGe2 series

An Unusual Triple-Decker Variant of the Tetragonal BaAl4-Structure Type: Synthesis, Structural Characterization, and Chemical Bonding of Sr3Cd8Ge4 and Eu3Cd8Ge4

“…2.5 Å), a number that is very close to the sum of the Pauling’s radii ( r Ge = 1.242 Å), these homoatomic interactions are rather strong. Similar distances are observed in many other ternary germanides, such as RE 2 CdGe 2 ( d Ge–Ge = 2.492(2)–2.522(1) Å), RE 2 MgGe 2 ( d Ge–Ge = 2.506(2)–2.548(1) Å), RE 2 InGe 2 ( d Ge–Ge = 2.504(5)–2.512(2) Å), RE 7 Li 8 Ge 10 ( d Ge–Ge = 2.528(2)–2.537(2) Å), RE 3 Li 4 Ge 4 ( d Ge–Ge = 2.514(2)–2.524(2) Å), etc., which are typical for Ge–Ge single bonds in germanides.…”

“…The initial reactions were done in a manner reminiscent of the synthesis of RE 2 CdGe 2 ( RE = rare-earth element) . A much larger (5 times) than stoichiometric amount of Cd metal was used deliberately with the aim for it to be a reactive flux.…”

“…These synthetic efforts did not yield phases isotypic with Sr 3 Cd 8 Ge 4 and Eu 3 Cd 8 Ge 4 . Only binary compounds were identified from the reactions of Ca, Cd, and Ge (main product was CaCd 6 ); the reactions of Ba, Cd, and Ge produced mostly BaCd 2 Ge 2 (or rather BaCd 2+ x Ge 2– x , as discussed later on), while the reactions of Yb, Cd, and Ge produced mostly Yb 2 CdGe 2 . The failure to obtain the desired AE 3 Cd 8 Ge 4 phases with Ca, Yb, or Ba (smallest and largest atomic size among the least electronegative metals in stable divalent states) indicates that besides electronic stability, geometric factors, i.e., crystal packing, are important for the realization of the structure in question.…”

A Series of Chalcogenide Borates RE6Ta2MgQB8O26 (RE = Sm, Eu, Gd; Q = S, Se) Featuring a B4O10 Cluster

“…In a comparison of the unit cell parameters and bond distances of 2 – 4 (Tables S1 and S2), it can be found that all of them decrease/increase regularly from 2 to 3 to 4 , obeying the lanthanide contraction rule. This phenomenon is often observed, such as in the series of RE 2 CdGe 2 , RE 4 S 4 Te 3 , MgRE 6 Si 2 S 14 , and RE 2 ZrSe 5 …”

Not Just Par for the Course: 73 Quaternary Germanides RE4M2XGe4 (RE = La–Nd, Sm, Gd–Tm, Lu; M = Mn–Ni; X = Ag, Cd) and the Search for Intermetallics with Low Thermal Conductivity

“…This versatile structure, which is remarkable for exhibiting well-ordered sites within a quaternary intermetallic compound, can be viewed in different ways (Figure ). It can be derived by cutting slabs from the tetragonal Mo 2 FeB 2 -type structure (which is adopted by many ternary germanides, such as RE 2 CdGe 2 and RE 2 InGe 2 , and is built up of a stacking of 3 2 434 nets) and shifting these slabs relative to each other. ,,, This viewpoint highlights the presence of Ge-centered trigonal prisms, which are commonly found in many intermetallic germanides, and X -centered tetragonal prisms. Alternatively, the structure can be regarded in terms of cationic RE atoms embedded within the tunnels of an anionic [ M 2 X Ge 4 ] framework, which is built up of ladders of edge-sharing M Ge 4 tetrahedra extending along the b -direction and X Ge 4 square planes.…”