342 



CLARKE : CHEMICAL STABILITY 



Lil. 



Nal. 



KI.. 



Rbl. 



Csl. 



152.0 

 159.0 

 126.1 

 137.5 

 38.3 



120.0 

 104.0 



87.9 



41.5 



5.8 



The bromide series is less complete and is inconclusive. Rubid- 

 ium bromide should be the least soluble, but the existing data 

 give this place to the potassium salt. The series needs further 

 investigation. As for the fluorides, the slight solubility of the 

 lithium and sodium salts is well known, and emphasizes the 

 present argument. To the nitrates of the alkalies the rule seems 

 not to apply; but in the sulfates, if we compare the metals 

 with the radicle S0 4 , the regularity appears. 



Here, as the masses of the radicles approach each other, the 

 solubility is lowered. The rule, however, as I have already indi- 

 cated, is not universal. Solubility is affected by various condi- 

 tions, such as hydrolysis, the formation of hydrates, etc.; but 

 in general it seems as if a stable compound is less easily dissociated 

 into ions than a comparatively unstable substance, and there- 

 fore, dissolves less freely. This subject is one which deserves 

 careful investigation. The agreements shown are something 

 more than mere coincidences. 



