New cubic cluster phases in the Mg–Ni–Ga system

The crystal structure of new Mg 9 Ni 6 Ga 14 and Mg 3 Ni 2 Ga compounds were investigated by single‐crystal diffraction. Both structures can be described as three‐core‐shell cluster compounds. In the Mg 6 Ni 9 Ga 14 structure, the [Ni 6 Ga 6 ] icosahedron is encapsulated within the [Mg 20 ] dodecahedron, which is again encapsulated within a [Ni 18 Ga 42 ] fullerene‐like truncated icosahedron, thus the three core–shell cluster [Ni 6 Ga 6 @Mg 20 @Ni 18 Ga 42 ] results. In the Mg 3 Ni 2 Ga structure, the [Mg 6 ] octahedron is encapsulated within the [Ni 12 Ga 6 ] flattened icosahedron in vertices of which there are 12 nickel atoms, and six lateral edges are centered by gallium atoms, which in turn is encapsulated within a [Mg 36 ] pseudo‐rhombicuboctahedron with 12 additional atoms centering the lateral faces; thus for Mg 3 Ni 2 Ga the three‐shell cluster is [Mg 6 @Ni 12 Ga 6 @Mg 36 ].