Structure D 2000Pt 29 Zn 49 , a Complex Defective AlB 2 -Type Derivative Structure. -The title compound is characterized by single crystal XRD. It crystallizes in the space group Amm2 with Z = 2 and forms a complex superstructure of a defective AlB2-type derivative of the order 58. Ordering of vacancies is accompanied by a particular distortion of defective graphite-like 6 3 nets consisting exclusively of Zn atoms. A mechanistic model is proposed elucidating how Pt 29 Zn 49 evolves from the eutectoid decomposition of the intermediate high temperature precursor Pt7Zn12. -(THIMMAIAH, S.; HARBRECHT*, B.; J.