Studies on the electrodeposition from organic solutions of metals that are difficult to deposit from aqueous solutions

Abstract

This paper deals with studies on electrodeposition from organic solutions of metals that are impossible (aluminium, beryllium, lithium) or difficult (tungsten, molybdenum) to electrodeposit from aqueous solutions. First, Al(CF 3COO) 3 and Be(CF 3COO) 2 were synthesized; their solubilities in various organic solvents and the specific electrical conductivities of the solutions were measured, and then electrodeposition of aluminium and beryllium was attempted with these solutions. Electrodeposition of aluminium and beryllium was found to be possible and, especially with aluminium, a smooth and lustrous deposit was obtained from a methanol solution with a cathodic current efficiency of about 30%. Electrodeposition of lithium was tried with organic solutions containing LiNO 3, LiClO 4 or LiCl as an electrolyte; lithium was found to be electrodeposited from a solution LiNO 3 and N,N-dimethylacetamide at an efficiency of over 70%. Electrodeposition of tungsten and molybdenum was attempted with organic solutions containing the phosphoric acid compounds of each metal as electrolyte. It was found that tungsten and molybdenum, each together with its respective oxide, could be electrodeposited from a solution of phosphotungstic acid, H 3BO 3, NH 4Cl, H 2O 2 and HCONH 2 and from a solution of phosphomolybdic acid, citric acid, NC 4Cl, H 2O 2 and HCONH 2 respectively.