50 RESEARCHES ON THE 



chloride, nitrate, and sulphate of Xanthocobalt, which are, as we write them at 

 present 



N0 2 .5NH 3 .Co 2 0,Cl 2 +HO. 



N0 2 .5NH 3 .Co 2 3 ,2N0 5 +HO. 



N0 2 .5NH 3 .Co 2 3 ,2S0 3 + HO. 



No chemical analyses could, probably, in substances of such high equivalents, 

 enable us to say with certainty that there may not be in these formulas an equiva- 

 lent of hydrogen too much. In this case the three formulae would read 



N0 3 .5NH 3 .Co 2 0,Cl 2 . 



N0 3 .5NH 3 .Co 2 3 ,2N0 5 . 



N0 3 .5NH 3 .Co 2 3 ,2S0 3 . 



The difficulty of analyzing these salts must also be fairly considered in forming 

 an opinion as to their constitution. We adopt provisionally the formula? first 

 given in the hope that a more extended study of the products of decomposition 

 will enable us hereafter to fix the constitution with certainty. In the mean time 

 we will only remark that the analyses of the nitrate of Xanthocobalt, which is of 

 all salts of the base the easiest to prepare in a state of absolute purity, correspond 

 exactly to the formula 



N0 2 . 5NH 3 .Co 2 3 ,2NO s + HO. 



CHLORIDE OF XANTHOCOBALT. 



The chloride of Xanthocobalt can be most readily prepared by decomposing a 

 solution of the sulpbate by chloride of barium. After separation of the sulphate 

 of baryta by filtration, a few drops of acetic acid may be added to the filtrate, 

 which, after evaporation by a gentle heat, will yield on standing large crystals of 

 the chloride. This process is in fact the only one by which we have been able as 

 yet to prepare this salt. 



The chloride of Xanthocobalt cannot be prepared by the direct action of a 

 current of NO x upon an ammoniacal solution of the chloride of cobalt. It is true 

 that in this case an abundance of a brown-yellow crystalline salt is obtained, which 

 might easily be mistaken for the chloride. This salt is, however,, a mixture of a 

 large quantity of the nitrate of Xanthocobalt with a much smaller quantity of 

 another salt, which appears to be the chloride of a distinct base, but which is not 

 yet fully studied. 1 



The equation which represents the formation of the chloride of Xanthocobalt 

 by double decomposition, is simply 



N0 2 .5NH 3 .Co 2 3 ,2S0 3 +2BaCl=2BaO,S0 3 +N0 2 .5NH 3 .Co 2 0,Cl 2 . 

 The chloride of Xanthocobalt crystallizes in brown-yellow crystals, which when 



1 It is this chloride in an impure state to which, in my Report on the Recent Progress of Organic 

 Chemistry, the formula 2N0 2 .5NH 3 .Co.,0 3 Cl, is attributed, and which is there called Dixanthocobalt. 

 W. G. 



