Crystal Structure and Properties of MgCo₄Ge₆

Abstract

MgCo 4 Ge 6 is a novel compound in the ternary system MgCo-Ge. Single crystals for a structure analysis were obtained from mixtures of the elements at high temperatures in sealed tantalum ampoules. The tetragonal structure [I4 2 m; a = 6.1725(9) and c = 8.660(2) Å; YRu 4 Sn 6 structure type] was determined by X-ray single crystal analysis and refined to R 1 = 0.027 for all data. The electronic structure is discussed by means of density of states and band-structure analyses on the

New Germanium‐rich Compounds SrCo5–xGe9 (x = 0.39 and 0.28) with Optimized Co–Ge Bonding

“…The CoϪGe distances in SrCo 4.72 Ge 9 are in the range of 2.29Ϫ2.76 A ˚and thus are similar to the ones in other known compounds such as MgCo 4 Ge 6 (2.29Ϫ2.47 A ˚) [2], MgCoGe (2.41 A ˚) [7], and MgCo 6 Ge 6 (range of 2.42Ϫ2.63 A ˚) [1] and also compare well with those in binary Co/Ge compounds: CoGe 2 (2.46Ϫ2.49 A ˚) [30], CoGe (2.34Ϫ2.63 A ˚) [31], Co 5 Ge 7 (2.39Ϫ2.73 A ˚) [13]. All cobalt and germanium atoms belong to the first coordination sphere of strontium, except for the Co5, which has an occupancy of 61 at.% in SrCo 4.61(1) Ge 9 and 72 at.% in…”

“…An absence of catalytic activity was also found for MgCo 4 Ge 6 [2]. In contrast the intermetallic compounds MgCo 6 Ge 6 and CaNi 4 Sn 2 have a citral conversion rate at 453 K of 17 % and 21 %, respectively [1,11].…”

Synthesis, Structure and Chemical Bonding of CaCo2Si2 and BaCo2Ge2 – Two New Compounds with ThCr2Si2 Structure Type

“…The corresponding –iCOHP value of 1.36 eV indicates a strong bond with covalent contributions as shown by the ELF maximum of η ( r ) = 0.3). In MgCo 4 Ge 6 36, the Co–Co distance of 2.58 Å is a little longer and the –iCOHP value of 1.06 eV somewhat smaller, but nevertheless an ELF maximum is shown at η ( r ) = 0.3.…”