154 



Proceedings of Indiana Academy of Science 



TABLE 2— Partition of HSCN between water and 1:4 EtOH-Et.O. 



In each experiment 10 cc. 4 normal NaSCN (SCN=0.04 equiv.) 



*Not recorded. 



In the above table, experiment 1 shows that NaSCN has a very 

 small but appreciable solubility in aqueous ether. Unfortunately, the 

 volumes of the aqueous and the ether layers in this experiment were not 

 recorded so that the ratios in the last column could not be corrected for 

 dissolved salt. The slight excess of thiocyanate is undoubtedly due to 

 this cause. The close approximation of the last ratio to unity shows 

 that the ether-soluble substance is practically all HSCN. The data 

 clearly show that this acid is far more soluble in ether than in water. 

 A small excess of mineral acid is sufficient to force nearly all the thio- 

 cyanate into the ether layer as HSCN. 



The data recorded in table .3 were obtained as follows. In a tall 

 glass-stoppered cylinder were placed 25 cc. of an aqueous solution of 

 KcCo(SCN), in which the cobalt content was 71.0 mg., 10 cc. of 4 normal 

 KSCN, the recorded volumes of 5 normal H.SO,, (in Expt. 9, 5 cc. of 33 

 normal acid) and sufficient 1:4 ethyl alcohol-ether to give approximately 

 equal layers. The cylinder was placed in a bath at 25° C. and frequently 

 shaken until equilibrium was reached. In .separate portions of the 

 ether layer acidity was determined by titration with NaOH and 

 phenolphthalein, SCN by titration with AgNO: and ferric alum, and 

 cobalt by evaporation with HlSO, and weighing as CoSO,. Acid in the 

 aqueous layer was also determined. In experiment 9, only 20 cc. of 

 the K^CoCSCN), solution were taken. 



The ratio ^/^ Co: SCN, together with the data of columns 8 and 12, 

 indicates a small .solubility of Co (SCN)- in aqueous ether containing 

 a little alcohol. This was confirmed using a sample of the purple 

 Co(SCN):.oH,0 which, although not very pure as shewn by analysis, , 

 showed all the reactions of this salt. When placed in ether the latter 

 assumed only a faint tinge of blue. The solubility calculated from the 

 data of experiment 1 is 0.347 mg. pej- cc. for the anhydrous salt. 



The ratios, H+:}^Co:SCX and (SCN-HCo): H+, confirm the con- 

 clusion from table 2 that HSCN is largely soluble in ether and that 

 its concentration in the ether layer increases rapidly as the mineral acid 

 in the aqueous layer is increased. 



The data throw no light on the formula of the ether-.soluble, blue 

 cobalt compound. In not too acid solutions about 20 mols. of HSCN 

 for each mol. of Co(SCN)2 are present. This may indicate either a 



