Nessler's reagent (K2HgI4 • KOH or K2HgI4 • NaOH) - is an aqueous alkaline solution dihydrate Potassium tetraiodomercurate (II). Externally, it is a liquid pale yellow, decaying under the influence of light.
Nessler's reagent is widely used in laboratory practice for the photometric determination and detection of NH3 at 436 nm (el 2.106). Furthermore, the ability to form a Nessler reagent causes metallic mercury its use for detection of aldehydes and alcohols, as well as the identification of such substances in hydroxyamino paper and thin layer chromatography.
Nessler's reagent is a mercury-containing substance that is responsible for its virulence. Hazard Class preparation 6. It should be prevented from entering the drug on the skin and mucous membranes, as well as inside the human body. All work is carried out with a reagent in the room with hatch.