ON BASIC SUBSTITUTIONS IN THE ZEOLITES 261 



The empirical formulx' are as follows : 



'■' Ba2pf,Al4g.,Sl,ooQ02798Cl37i. 



■t> i*'l;',?7-''^.'>-<3'^'lOOo'^31t-l*-''21' 



^ l^<*101-^'486'^'lllOo'J3l>H*-'i:l2' 



Although the replacement of monoxide bases by barium is 

 complete, the products are evidently mixtures, and their ratios 

 are not easy to interpret. The fact that yl, rich in chlorine, 

 and B^ almost chlorine free, both came from the same melt, 

 indicates a breaking down of the molecules. This suspicion 

 is contirmed b}^ a study of the leach waters. In the washings 

 from A and B, Mr. McNeil found 15.85 per cent, of the original 

 silica of the chabazite, with 13.10 per cent, of the alumina. 

 The leachings from C similarly contained 20.3 of the silica and 

 11.96 of the alumina. The flocculent compound B approxi- 

 mates ver}^ roughly in composition to a salt of the type BagAlg 

 (SiOJ^(Si30g)2, but A is not reducible to any rational formula. 

 It is probable that a series of reactions took place, in which 

 barium chabazite was first formed and afterwards partly broken 

 down or otherwise modified by the continued action of the 

 molten barium chloride. The solvent effect of the latter salt 

 upon silica and alumina is quite marked, and was studied by 

 Mr. jNIcNeil upon the pure oxides or hydroxides. In four ex- 

 periments, one gramme of finely divided silica was acted upon 

 by fused barium chloride for 30 minutes. Upon leaching and 

 filtering, the following quantities of silica were found to have 

 been dissolved : 



1. 0.0973 gramme, = 9.73 per cent. 



2. .0592 " =5-92 " " 

 3- -0945 " = 9-45 " " 

 4. .0771 " — 7.71 " " 



When aluminum hydroxide equivalent to one gramme of AI2O3 

 was fused for 30 minutes with 20 grammes of BaCU, 11. 15 per 

 cent, of it went into solution in the washings. Ignited alumina, 

 however, was not attacked. From these experiments it seems 

 probable that when zeolitic derivatives are formed and partly 

 decomposed, the decomposition products pass largely into solu- 

 tion upon leaching. Irregularity in the composition of the 

 residues is therefore to be expected ; and in the order which 



