What is "tetraiodonickelate"

Tetraiodonickelate is a complex ion of nickel with four iodide atoms [NiI] arranged in a tetrahedron. [NiI] is red in solution. This colour is due to absorption around 530 nm and below 450 nm. Maximum light transmission is around 620 nm, which is red. A broad weak absorption in the near infrared is at 740 nm. The magnetic moment is anomalously low.

A mixture of lithium iodide and nickel iodide in water or methanol can partition NiI ions into a cyclohexane- amine mixture. The solution formed is blood red.