1903.] P. C. Ray — Constitution of Dimer xur 'ammonium Salts. 3 



(2) 72, 215.] Again, the mercuroxy-ammonium chloride, if it exists at 

 all, when heated, decomposes into ammonia, nitrogen, water, and calomel 

 (Kane). But both the chloride and the bromide as obtained by me de- 

 compose according to the equation: 2NHg 2 X.H 2 0=N 2 -f 2 HgX + Hg 2 + 

 H 2 — a reaction which has been established quantitatively, as will be 

 shown in a subsequent communication. Scarcely a trace of ammonia 

 could be detected even by Nessler's reagent; I thus find myself in agree- 

 ment with Weyl's observations, though his salt is non-hydrated. Andre, 

 as has been already noted, goes halfway between Kane and Weyl and 

 believes in the existence of two distinct compounds: NHg 2 Cl and OHg 2 

 = NH^Cl, often formed side by side. 



In the case of infusible white precipitate, as we have already seen, 

 Kane attributes to it the formula, NH 2 HgCl. Rammelsberg, on the other 

 hand, looks upon it as a " double salt," having the composition, NHg 2 Cl+ 

 NH^Cl. He is supported in his contention by the compound "dissocia- 

 ting" into NHg 2 Gl and NH 4 01 on treatment with H.OH, or better K.OH. 

 A study of the decomposition of the compound under the action of heat, 

 on the other hand, corroborates the other view of its constitution. Tor, 

 if Rammelsberg's formula be accepted, the decomposition might be ex- 

 pected on the following lines (c/. decomposition under heat of ammonio- 

 magnesium chloride) : — 



NHg 2 Cl NH 4 C1. 



I 



NH g2 Cl + NH 4 Cl, 



I 



N + Hg + HgCl + NH 4 Cl. 



But the amount of ammonium chloride was relatively insufficient, 

 nor was there any free mercury found. The slight amount of ammonium 

 chloride may well be due to a secondary reaction between calomel and 

 ammonia. Here the decomposition is found rather to agree with Kane's 

 view of the constitution. 



We thus find that both these views about the constitution of the in- 

 fusible white precipitate are supported by experimental data, which can 

 well be explained by having recourse to considerations of "tautomerism." 

 Although we know little or next to nothing about the molecular configura- 

 tion of the so-called "double salts," it would be interesting to note that 

 such instances of " tautomerism " are given in inorganic chemistry, (c/. 

 in this respect, Hantzsch, on the tautomerism of hyponitrous acid and its 

 salts, Annalen, Bd. 292, 340). 



The so-called mercuroxy-ammonium chloride, NH 2 ( Hg.OHg)Cl, 



