Dimethylglyoxime

• Diacetyldioxime
• DMG
• DAD
• 2,3- Butandiondioxim
• Tschugaeff reagent

Colorless, odorless powder

Fixed

• 245-246 ° C ( decomposition)
• 240-241 ° C ( decomposition)

Slightly soluble in water (0.6 g · l-1 at 20 ° C)

Attention

250 mg · kg -1 ( LD50, rat, oral)

-199.7 KJ / mol

Template: Infobox chemical / molecular formula search available

Dimethylglyoxime, also diacetyldioxime ( DADO ), is an organic chemical complexing agent.

Properties

Dimethylglyoxime is a complexing agent which forms colored chelate with heavy metal salts such as Ni, Fe, Bi, Co, Cu, Pb, Pt, Pd, Au, Re, and salts.

Especially the pink to raspberry red, very slightly soluble bis ( diacetylglyoximato ) nickel ( II) ( nickel - dimethylglyoxime complex, [ Ni ( dmg ) 2] ) in ammoniacal solution serves as a qualitative nickel ( II) detection and quantitative determination ( photometry ) used for nickel salts. This chelate has a square planar construction. In the solid state, the complexes formed into molecular stacks, be the Ni -Ni distances each 325 pm.

Moreover, the formation of the nickel complex is also used for the separation of cobalt ( II ), since this is an analog, but in contrast, water-soluble complex with dimethylglyoxime.

The complex was first described in 1905 by Lev Alexandrovich Chugaev.

The coloration can be detected even up to a dilution of 1:106. With citric acid or tartaric acid in alkaline solution interfering ions can be masked.

In ammoniacal solutions, the following staining / precipitates form:

• Nickel: raspberry
• Copper: brown-red
• Iron (II): red
• Cobalt: brown-red
• Bismuth: intense yellow
• Lead: white ( voluminous, finely distributed )
• Palladium: yellow yellowish

Representation and equation for the nickel complex

Reagent

• Saturated solution of dimethylglyoxime in 96% ethanol
• Aqueous solution containing 0.1 mol / l disodium bis ( dimethylglyoximate )
• Dimethylglyoxime solution (1 % in methanol)