Ca 5 Ni 17 Ge 8 – A Complex Intermetallic Compound Combining Various Structure Motifs of Alkaline‐Earth Nickel Germanides

The intermetallic compound Ca 5 Ni 17 Ge 8 was prepared by arc melting mixtures of the elements and subsequent annealing under argon atmosphere. The compound crystallizes in a new structure type with the space group Amm 2, Z = 2, a = 4.0255(2) Å, b = 25.226(2) Å, c = 8.9861(6) Å and wR 2 = 0.083 (all data).Ca 5 Ni 17 Ge 8 consists of a $\rm^{3}_{\infty}$ [Ni 17 Ge 8 ] network in whose cavities the calcium atoms are situated. The three‐dimensional network comprises a unusual large diversity of structural motifs that are known from other compounds of the systems Ae /Ni/Ge ( Ae : Ca, Sr, Ba), such as the coordination environments of the calcium atoms reminiscent to those in Ca 7 Ni 49 Ge 22 and Ca 15 Ni 68 Ge 37 as well as various Ni‐Ge structural motifs which occur similarly in Ca 2 Ni 3 Ge 2 , BaNi 2 Ge, SrNi 2 Ge, Ni 3 Sn 2 and Ni 3 Sn.