Preparation and Double-Helix Icosahedra Structure of delta-Co2Zn15

The first known example of a regular face-sharing icosahedra helix is presented in the novel crystal structure of delta-Co2Zn15, solved and refined from single-crystal X-ray and neutron powder diffraction data. The compound delta-Co2Zn15 is also the first example of an intermetallic compound crystallizing in the acentric hexagonal space group P62. The parameters from the single crystal refinement are a=11.292(2) ?, c=7.750(1) ?, Z=4, and Rw=0.025.