156 Intelligence and Miscellaneous Articles. 



his results therefore agree with those of Berzelius, Graham and Clark. 

 — Journ. de Pharm. et de Ch., Dec. 1845. 



ON SEVERAL NEW SERIES OF DOUBLE OXALATES. BY M. REES 



HEECE. 



These salts were discovered in investigating the action of alkaline 

 and earthy bases on the oxalates of the sesquioxides. 



It is well known that the salts of lime produce but a slight pre- 

 cipitation of oxalate of lime in a moderately concentrated solution 

 of the oxalates of the sesquioxides of iron and chromium, &c, and 

 none in a very dilute solution of oxalate of chromium and potash, a 

 salt discovered by Prof. Gregory, and in which there are 3 equiv. 

 of oxalic acid combined with the alkaline base. A concentrated 

 solution of the same salts gives rise to an abundant precipitate, 

 which has been considered as oxalate of lime, but in which I found 

 a considerable proportion of chromium. These were the facts which 

 led me to pursue this inquiry. 



The combination by means of which I have prepared the double 

 salts which are the objects of this memoir, is an oxalate of chromium 

 and ammonia, having the same formula as the salt of Mr. Gregory ; 

 but it is preferable to this on account of its great solubility. 



A concentrated solution of this salt, mixed with its volume of 

 chloride of strontium, barium or calcium, yields voluminous pre- 

 cipitates, which, separated from the mother-leys and recrystallized, 

 have the following composition : — 



Oxalate of chrome and barytes (A) 3C 2 O 3 -f Cr 2 O 3 -j- 3(C 2 O 3 BaO) + 12H0. 

 Oxalate of chrome and barytes (B) 3C 2 O 3 -f Cr 2 O 3 + 2(C 2 O 3 BaO) + 18H0. 

 Oxalate of chrome and strontian ... 3C 2 O 3 + Cr 2 O 3 + 3(C 2 O 3 SrO) -f 18 HO. 

 Oxalate of chrome and lime 2(3O0 3 + Cr 2 3 ) + 3(C 2 3 CaO) -f 36HO. 



If oxide of iron is substituted for the oxide of chromium, we obtain 

 the corresponding salts with an iron base, and which are represented 

 by the following formulse : — 



Oxalate of iron and barytes 3C 2 S + Fe J 3 -f- 3(C 2 3 BaO) -f 7H0. 



Oxalate of iron and barytes 3C 2 3 + Fe 2 3 + 3(C 2 3 BaO) + 12H0. 



Oxalate of iron and strontian 3C 2 3 + Fe 2 3 + 3(C 2 3 SrO) + 18H0. 



The oxalate of iron and of lime does not crystallize. 



If alumina is substituted for the oxide of chromium, we obtain 

 similar salts, which are represented by — 



Oxalate of alumina and barytes 3C 2 S + A1 2 3 + 3(C 2 3 BaO) + 10HO. 



Oxalate of alumina and barytes 3C 2 O 3 + Al 2 O 3 + 3(C 2 O 3 BaO) + 30HO. 



Oxalate of alumina and strontian 3C 2 3 + A1 2 3 + 2(C 2 3 SrO) + 18H0. 



The oxalate of alumina and lime cannot be isolated in a state of 

 purity, on account of its insolubility. 



These salts crystallize in small silky needles ; those of the oxide 

 of chromium are of a dark violet colour, those of iron of a greenish- 

 yellow, and those of alumina of a brilliant white. They are soluble 

 in about 30 times their weight of boiling water (excepting the salts 

 of lime and oxide of chromium, of alumina and strontia, which are 

 decomposed by water) ; they are scarcely soluble in cold. All the 

 alkalies decompose them by precipitating the sesquioxide and earthy 



