ON BASIC SUBSTITUTIONS IN THE ZEOLITES 



•59 



Here again a perfect replacement of sodium has been effected, 

 and a close approximation to the true barium analcite is shown 

 in the analyses. 



Stilbite, which is a calcium alumosilicate, has also been care- 

 fully studied. Mr. Steiger prepared its ammonium and thallium 

 derivatives, and Mr. McNeil obtained a sodium salt by fusing 

 the mineral with sodium chloride. The analvses are as follows : 



100.30 



100.03 



99-83 



If we throw out the water of cr3^stallization as extraneous, the 

 molecular ratios give the following empirical formulae for the 

 anhydrous compounds. The tw^o sodium preparations are aver- 

 aged together, and the monoxide bases are united under the 

 general symbol R/O. 



Stilbite (Ca salt) R..,/Al36„S:ioo(A7:)«- 



NH, salt R373'Al,5«Si,oooO.,7o5Cl32- 



Tl salt R:i76 ^'^'376'^'l0O0^2751* 



Na salt R408'^^l:)67yiioooOmiCl38. 



The anal3'ses show clearly the e.xtent of the substitutions 

 effected in stilbite, and the formulae indicate the persistency of 

 the original type. 



Chabazite, like stilbite, is essentially a calcium aluminum 

 trisilicate, and it yields substitution derivatives quite readily. 

 It has, however, a noteworthy tendency to take up extra atoms 

 or groups of atoms, and the analyses consequently show the 

 presence of chlorides or nitrates thus retained. The figures in 

 the following table represent some of these products. 



