Answer is: name of the complex ion [Cu(CN)₆]⁴⁻ is hexacyanocuprate(II).
First give name of the ligands (in this example ligand is cyano anion CN⁻), in alphabetical order, then the metal atom or ion (in this complex compound metal ion is copper Cu²⁺). Prefix for six ligands is hexa-. This is anionic complex, so name of the copper is cuprate and (II) stands for oxidation number of copper.
