ON BASIC SUBSTITUTIONS IN THE ZEOLITES 265 



6SiO,.6Al03. 1 2Ca0.4CaCl ; 

 and 



5SiO,.8Al03. 1 2Ca0.4CaBr,. 



These substances, however, have no apparent relation to our 

 zeolitic derivatives, nor can they be simply formulated structur- 

 ally. By fusing kaolin with strontium and barium chlorides he 

 obtained the basic salts 



4Sr0.4AU03.7Si02; 

 and 



4Ba0.4Al203.7Si02; 



which, in their physical properties, resemble nepheline. 



For thomsonite, a silicate of quite different ratios from stilbite 

 and chabazite, three derivatives have been prepared. The 

 anal^'ses are as follows : 



Steiger. Steiger. Steiger. McNeil. 



Thomsonite. NH4 salt. Ag salt. Na Salt. 



SiOj 41.13 42.65 34.99 44.00 



AI2O3 29.58 31.34 24.02 32.S5 



CaO 11.25 9-23 7-54 2.75 



Na,0 5.31 2.48 .74 18.32 



(NHJ2O 4.0S 



Ag,0 24.32 



H2O 13.13 10.40 8.39 



CI 3-OI 



100.40 100. iS 100.00 ic)o.93 



Less O .68 



100.25 



From these the subjoined empirical formulae follow, calculated 

 for the anhydrous compounds. 



Thomsonite Rsss'Alg^SijoooOneM' 



NH4 salt R7il6''Al863Sil000O:<693- 



Ag salt Rse^'AlgogSiioooOagii- 



Na salt R9i/Aly,,jSiiooo0373oCli,6. 



The thomsonite itself conforms sharply to the normal ratio of 

 Al3Na3X3, in which X3 represents SiO^ + SiaOg. The propor- 

 tion of Si30g however, is only one eleventh. The sodium deriv- 

 ative, which contains chlorine, appears to resemble the com- 

 pounds derived from stilbite and chabazite, and may be regarded 

 as ver}' near the mixture 



