The tetrabromonickelate anion contains a doubly-charged nickel atom (Ni2+) surrounded by four bromide ions in a tetrahedral arrangement.
[1] Solvents that can dissolve tetrabromonickelate include acetone, acetonitrile, methyl ethyl ketone, and nitromethane.
[7] Tetraphenylphosphonium tetrabromonickelate(II) can be made from nickel bromide, triphenylphosphine, and bromobenzene by heating them together in a sealed tube at 250 °C.
[9] bis-(benzo[e]-1,3-dithiepan-2-diethylimmonium) tetrabromonickelate, abbreviated as (xdtc)2NiBr4, has dark blue crystals that melt at 166 °C.
[12] One bromine atom can be substituted by other ligands, such as triphenylphosphine, to make a dark green triphenylphosphinetribromonickelate ion.