Spectrophotometric estimation of molybdenum with disodiom cis-1,2-dicyanoetfaylene-1,2-dithiolate

A rapid spectrophotometnc method is described for estimation of molybdenum by use of the molybdenum-dicyanoethytene dithiolate complex. The bright green complex has its absorption maximum at 665 nm and in 50% aqueous acetonitrilc is stable for several days at 3M hydrochloric add concentration, The estimation is more sélective if longer wavelengths and high acidity are used. Beer's law is obeyed over the range 1-16 ppm molybdenum, optimum range 4-16 ppm. The overall formation constant Of the complex with metal to ligand ratio of 1:4 is 5 +/- 2 x 10(18). The molar absorptivity is 5.05 x 10(3) l.mole(-1).cm(-1).