Tris(4 bromophenyl)ammoniumyl hexachloroantimonate

Tris(4-bromophenyl)ammoniumyl hexachloroantimonate is the organic compound with the formula [(4-BrC₆H₄)₃N]SbCl₆. Commonly known as magic blue, it is the hexachloroantimonate salt of an amine radical cation. It is a blue solid that reacts with many solvents but is soluble in acetonitrile. The compound is a popular oxidizing agent in organic and organometallic chemistry, with a reduction potential of 0.67 V vs. ferrocene/ferrocenium (MeCN solution) or 0.70 V vs. ferrocene/ferrocenium (dichloromethane solution).

The structure of the cation consists of a three-bladed propeller structure with a planar amine. It is nearly identical to the parent triphenylamine. The weakly coordinating anion is SbCl₆⁻, which is octahedral.