Tetra-n-butylammonium iodide (TBAI) forms associations in chloroform and aqueous solutions. A TBAI solution in chloroform
extracts hydroiodic acid by addition. From 0.5M hydroiodic acid medium cadmium is quantitatively extracted into a TBAI solution
in chloroform. Under these conditions zinc is not extracted. This makes possible the extractive separation of cadmium from
zinc in micro-or macroamounts.