492-99-9

beige to brown crystalline powder or needles

1,2-Cyclohexanedione dioxime acts as a chelating ligand forming complexes with many transition metal ions like Co, Fe and Ni. It is used in photometric detection of metal ions.

Analytical reagent for nickel and palladium.

Nioxime is an analogue of dimethylglyoxime, with which, in general, the same determinations can be accomplished as with dimethylglyoxime. It is, however, more soluble in water than dimethylglyoxime so that it can be applied as an aqueous solution for the precipitation of metal complexes. In this way the potential error caused by the increased solubility of the complex in the presence of alcohol is eliminated. In gravimetric determinations the higher molecular weight of nioxime presents a further advantage (the molecular weight of the nioxime complex of nickel is 340.99, while that of the nickel complex of dimethylglyoxime is 288.91).
Recently nioxime has been successfully applied for the gravimetric determination of bismuth/34 , 477) The bismuth nioxime complex was precipitated selectively from a solution containing about 30 cations (among them nickel and palladium) using the masking action of EDTA at about pH 12.

Crystallise Nioxime from alcohol/water and dry it in a vacuum at 40o. Also 2.5g of oxime have been recrystallised from 550mL of H2O using Fe free Norit. It forms complexes with Ni and Pd. [Hach et al. Org Synth 32 35 1952.] [Beilstein 7 IV 1982.]