68 
DE. E. EEA^^KLAJSTD’S EESEAECHES ON OEG-ANO-METALLIC BODIES. 
appear to be formed under similar circumstances, with other salts of dinitroetbylic acid. 
These compounds are evidently of the same nature as that produced by the union of 
zincethyl with iodide of zinc, which is formed in such large quantity during the prepara- 
tion of zincethyl. 
Dinitro ethylate of zinc crystallizes in minute colourless needles containing half an 
equivalent of water, which they retain when exposed over sulphuric acid in vacuo. They 
fuse below 100° C., and gradually become anhydrous at this temperature. They are very 
soluble in water and in alcohol. The concentrated aqueous solution sohdifi.es on cooling 
to a white fibrous crystalline mass. Heated suddenly in air to a temperature of about 
300°, this salt does not deflagrate, but it inflames, burning rapidly with a beautiful bluish 
green flame. When dry dinitroethylate of zinc is treated with concentrated sulphmic 
acid, and the vessel containing those ingredients is placed in a freezing mixture, dinitro- 
ethyhc acid is liberated ; but it is so unstable, that when the temperatime rises a few 
degrees it begins to effervesce violently, and is rapidly decomposed with the evolution of 
gases and white vapours. A dilute solution is somewhat more stable ; it may be pre- 
pared either by decomposing a dilute solution of dinitroethylate of zinc with dilute sul- 
phuric acid and then distilling in vacuo, or by adding to a dilute solution of the baiyta- 
salt just sufficient sulphuric acid to precipitate the base. Dilute dinitroethyhc acid thus 
prepared possesses a pungent odour, somewhat resemhling that of the nitro-fatty acids, 
and an acid taste. It reddens litmus-paper strongly, and gradually decomposes even at 
ordinary temperatures. 
The acid procured by distillation in vacuo being treated with carbonate of silver, the 
latter dissolved with evolution of carbonic acid. The filtered solution, evaporated over 
sulphuric acid, deposited light flocculent crystals of dinitroethylate of silver, which 
blackened rapidly. They gave, by treatment mth nitric acid and subsequent ignition, 
55-85 per cent, of metallic silver. The formula N 2 C 4 H 5 04 Ag reqiures 54-82 per cent. 
Another portion of the dilute acid, procured by the decomposition of the baiyta-salt as 
described above, was saturated with magnesia, evaporated to dryness, and the residue 
treated with strong alcohol. The filtered alcohohc solution, wliich contained no trace 
of sulphuric acid, gave, on evaporation, dinitroethylate of magnesia, which, by treat- 
ment with nitric acid and ignition, yielded 19-64 per cent, of magnesia. Tlie formula 
Na C 4 Hj O 4 Mg requires 19-80 per cent. 
The salts of dinitroethylic acid are all soluble in water and alcohol, and most of them 
crystallize with more or less difficulty. They are all Holently acted upon by concen- 
trated nitric acid, the dinitroethylic acid being enthely decomposed and a nitrate of the 
constituent base produced. Dilute nitric acid acts in the same maimer, but more slowly. 
They all fuse at a temperatm-e httle above 100° C. The potash, soda, hme, and baryta 
salts deflagrate explosively, like loose gunpowder, at a temperatm-e considerably below- 
redness. 
