162 PROCEEDINGS OF THE AMERICAN ACADEMY 



Calcic BZ-Dibrompyromucate, Ca(C5HBr203)2 . 3 HgO. — On neutral- 

 izing a boiling aqueous solution of the acid with calcic carbonate, we 

 obtained the calcium salt in small clustered prisms, which we purified 

 by recrystallization from boiling water. The air-dried salt contained 

 three molecules of water, one of which it lost over sulphuric acid. 



I. 1.1374 grm. of air-dried salt lost over sulphuric acid 0,0275 grm. 

 up, and in addition 0.0706 grm. HgO at 110°. 

 II. 1.4733 grm. of the air-dried salt lost at 112° 0.0984 grm. B.f>. 



Calculated for Found. 



CaCCsHBroOs).. . 3 H,0. I. II. 



H2O 2.85 2.42 



3 HP 8.56 8.63 8.36 



I. 0.4709 grm. of the anhydrous salt gave on ignition with H^SO^ 

 0.1107 grm. CaSO,. 

 II. 0.6026 grm. of the anhydrous salt gave on ignition with HgSO^ 

 0.1387 grm. CaSO,. 



Ca 



The solubility of the salt in cold water we determined by evapora- 

 tion and ignition with sulphuric acid. 



I. 39.5194 grm. of a solution saturated at 17° gave 0.0288 grm. 



CaSO,. 

 II. 50.3735 grm. of a solution saturated at 17° gave 0.0344 grm. 

 CaSO^. 



The aqueous solution saturated at 1 7° therefore contained the fol- 

 lowing percentages of the anhydrous salt : — 



I. II. 



0.31 0.29 



Argentic ft^-Vibrompyromucate, AgCJiBr.p„. — From an aqueous 

 solution of the acid argentic nitrate precipitates the silver salt in the 

 form of fine clustered needles, which may be recrystallized from liot 

 water without essential decomposition. For analysis we prepared it 

 by precipitating a solution of argentic nitrate with a solution of the 

 acid neutralized by ammonic hydrate. 



0.3275 grm. of the salt dried over sulphuric acid gave 0.1646 grm. 

 AgBr. 



Calculated for AgCjHBrjO.,. Found. 



Ag 28.65 28.87 



