THE OXALATE OE MANGANESE. 31 



of a solution of one part of manganese-salt in 100 of water, by means 

 of oxalate of potassa ; and this compound is stated to lose no water 

 at 212°. F. Nothing is said with regard to the amount of water in 

 the precipitate obtained from concentrated manganese solutions by 

 oxalic acid. 



There is evidently some error in the above statement, for the for- 

 mula MnO, C 2 O s +5 HO requires 38,60 per cent, of water, and 

 Mn 0, C 2 3 +3 HO requires 27.39. 



In the 89th volume of the Annalen der Chemie and Pharmacie, 

 Hausmann and Lowenthal give an analysis of the oxalate obtained 

 by acting on freshly precipitated carbonate of manganese with oxalic 

 acid, from which they deduce the formula Mn 0, C 2 3 +2 HO, for 

 the salt dried at 212°. F. 



The following experiments were made for the purpose of explain- 

 ing the discrepancy. 



Strong solutions of sulphate of manganese were precipitated by 

 saturated solutions of oxalic acid, a "granular white precipitate was 

 obtained in both cases, which did not lose water at 212°. F. I. and II. 



Similar solutions were mixed when boiling. III. 



Sulphate of manganese was dissolved in 30 parts of water, and 

 oxalic acid added, a light pinkish crystalline precipitate was formed 

 after a time, which, in the course of a few days, changed into a per- 

 fectly white granular powder. IV. 



Sulphate of manganese was dissolved in 30 parts of water, and a 

 solution of oxalate of potassa added, a light pinkish crysl alline pre- 

 cipitate gradually formed, having the appearance and lightness of 

 benzoic acid, it absorbed and retained water like a sponge, and re- 

 mained unchanged in the air at ordinary temperatures, but became 

 perfectly white at 212°. F. V. 



Sulphate of manganese was dissolved in 100 parts of water, and 

 oxalate of potassa added; the same pink salt was obtained. VI. 

 This should be the compound described by Graham, with 5 HO. 



WHITE SALT. 



I. 1.391 grms. gave 0.5890 Mn 3 4 = 39 38 per cent. MnO 



11/ 1.292 " " 0.5566 " = 40.07 " " 



III. 1.717 " " 0.7510 " = 40.68 " " 



IV. 1.295 " " 0.5545 " = 39.83 « " 



Mean 39.99. 

 The formula MnO, C 2 3 +2 HO requires 39.72. 



