so JOURNAL OF THE 



AN ATTExMPT AT FORMING COPPER AND 



BARIUM ACETATE. 



J. C. ROBERTS. 



The double acetate of copper and calciuiu is described in Watts'" 

 Dictionary (I, 15), but no mention is made of a corresponding dou- 

 ble acetate with barium. The preparation of this body was under- 

 taken as an exercise in manipulatioii and an account of the experi- 

 ments is here given as showing some of the difficulties which pre- 

 vented its formation. 



Pure, crystallized copper acetate was prepared and also a supply 

 of pure barium acetate. A mixture of the concentrated solutions 

 of these salts with an excess of barium acetate was evaporated on 

 a water-bath to thick syrupy consistence, giving a deep blue liquid^ 

 from which after four days' evaporating a mass of crystals settled out. 

 Thesr crystals seemed blue but on thorough washing with alcohol 

 proved to be barium acetate. 



The two salts in concentrated solution were then mixed in the 

 proportion of their molecular weights. One portion was still further 

 concentrated by evaporation on a water -bath and then exposed in 

 a crystallizing dish to a temperature of 20^ — 25° c. The other was 

 placed under a glass receiver over sulphuric acid. Green crystals 

 formed in both of these dishes, alternating with the settling out of 

 flocculent masses of some bluish substance. These masses had a 

 silky, crystalline appearance. All green crystals were removed, the 

 blue mass washed and copper and barium d terminations made. A 

 little Licetic acid was generally added to effect complete solution 

 before analysis. The barium in three different samples ranged from 

 3.90 to 4. 10 per cent. , but seemed an accidental impurity from in- 

 sufficient washing. The copper in two determinations gave 48.82 

 and 45.85 per cent. The amounts procurable for analysis were how- 

 ever very small. The mass seemed to be then a basic acetate. It 

 was found that the production of this blue settling out could be 

 greatly hastened by adding alcohol to the mixed solutions and allow- 

 ing the dish to stand in a free current of air at about 20° c. Two 

 specimens gotten in this way were analysed giving copper=35.47 

 per cent. ; bariup = .OOper cent., and from the second copper=34.25 



