When nitromethane is mixed with a concentrated solution of ammonium hydroxide, after several hours the liquid develops a dark brown color and a
crystal substance begins to form. The small crystals formed are colored and difficult to purify.
In a bottle, 20 cc (cm3) of pure nitromethane is mixed with 8 cc of the ammonia solution, and ammonia gas is then bubbled into the mixture until it is
complely saturated (until no more gas can dissolve). A cap is then placed on the bottle and the bottle is kept under 10 °C for about a day. The
crystals which separate out are then removed and gently crushed into a moist powder. The powder is placed on an unglazed clay tile to draw out the
water and allowed to air dry. The residual liquid still in the bottle is again saturated with ammonia gas and the process is repeated as before. This
method will yield about 12 grams of the crystal substance.
The crystals are soluble in methanol, less soluble in ethanol, and nearly insoluble in ether or chloroform. When the crystals are heated, they
decompose, producing some poisonous hydrogen cyanide gas.
The crystals are ammonium 2-nitroethanaloximate, with the formula
NH4(+) C2H3N2O3(-).
The structure can be written HON=CHCH=NO2(-).
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