22 MOLYBDENUM BLUE 



This agrees with experimental values within 4-5%. 



The wt. of gas given off , , ' ' ^ X.2669= .0898 g. 



Aioj 08 Ho O 



This agrees within 1-1/3% of epxerimental result. 



The formula AI03O82H2 O was tried, but gave poor agree- 

 ment. 



From these calculations, it has been shown that the formula 

 M03 Os Ha O agrees most closely with actual weights of analysis. 

 It should be noted also, that this formula comes the nearest 

 to the molecular weight as determined by Dumanski. He found 

 it to be 440. This formula M03 Og H^ O gives molecular weight 

 of 434; M03 Os 416 and Mo, Og SH^ = 506. 



It has been found, as noted above, that the dried hydrogel 

 is soluble in absolute alcohol. Now Zsigmondy, in his "Chem- 

 istry of Colloids," "(T. Spear, 1917)" discussing Silicic Acid 

 Organogels, states: "The fact that water may be replaced by 

 other substances as solvents, without any marked change in 

 the character of the gel, points clearly, as Van Bemmelen has 

 noted, to the assumption, that water is not there as a hydrate 

 chemically combined, but is absorbed water that fills the spaces 

 between the ultramicrons." He gives G. Tschermak; (Zeit. f. 

 phys. Chemie. 53, 349-367), (1905); G. Tammann; (Zeit f. 

 Anorg Chemie. 71, 375), (1911); as references. 



It is obvious, then, that the formula for Molybdenum 

 Blue given, in the same volume, is incorrect. If we accept the 

 work of Bemmelen, any formula which shows one or more 

 molecules of water of hydration must be discarded. This 

 leaves just Mo^Oj, or M03 Og. Of these M03 Og is the better. 



Ostwald in his "Inorganic Chemistry," says: "Between this 

 (Mo O2) and trioxide are the readily formed Blue compounds, 

 the composition of which varies^ and cannot be characterized 

 with sufficient sharpness." This variation may be due to the 

 different formula-weights of water enclosed by the ultrami- 

 crons. Certainly the formula MojOg HjO best expresses the 



