• Liquid ammonia;
  • Amides;
  • Zirconium;
  • Structure elucidation;
  • Quantum chemistry


We present the low-temperature synthesis of potassium hexaamido zirconate(IV) from the transition metal tetrafluoride and thealkali metal dissolved in liquid ammonia at –40 °C. Potassium hexaamido zirconate(IV) K2[Zr(NH2)6] is the first ternary amide reported for elements of group 4 of the periodic table It crystallizes with a novel structure type in the trigonal space group Requation imagec with a = 6.5422(2) Å, c = 32.824(2) Å, V = 1216.66(9) Å3, Z = 6 and c/a = 5.017. The structure can be derived from the K2PtCl6 type. The compound contains discrete D3-symmetric [Zr(NH2)6]2– anions which differ significantly from octahedral shape. Quantum chemical calculations show the distortion to arise from a splitting of degenerate d-orbitals on the zirconium atom leading to a significant gain in energy.