424 



Allen, Crenshaw, and Merwin- 



Table X. 



Influence of acid on the crystalline form of ZnS at 250° . 

 tained 2% ZnSOiJH^O and were precipitated by 

 NHtCNS. 



All solutions con- 

 HzS from 0'5 a. 





Final 



H 2 S0 4 



in wt. % 



Time 





Product 







Initial 

 H 2 S0 4 



Composition of Crystalline 

 Part 



% A 



Linorphous 



in wt. % 



% wurtzite % sphalerite 





1-0 



0-6 



3 



days 



50 



50 





60 



1-0 



0*7 



4 



u 



? 



? 





80 



1-5 



1-2 



3 



a 



60 



40 





50 



2-0 



0-9 



4 



a 



70 



30 





15 



2-0 



1-1 



3 



a 



5 



95 





5 



2-0 



1-2 



5 



a 



99 



1 









2-5 



1-7 



5 



a 



99 



1 





5 



4-0 



2-5 



2 



u 



100 













5-0 



....f 



2 



a 



100 









5 



6-0 



8-0 



2-9 

 5-6 



3 

 3 



u 

 u 





no precipitate of ZnS 

 u it tt 





10-0 



7-0 



2 



a 





a a 



n 













Table XI. 







Influence of acid on 

 tained 2% ZnSO 

 NHtCNS. 



the crystalline form of ZnS at 300°. All solutions con- 

 i.7H<zO and were precipitated by H?S from 0'5 g. 





Final 



H 2 S0 4 



in wt. % 



Time 





Product 







Initial 

 H 2 S0 4 



Composition of Crystalline 

 Part 



%A 



.morphous 



in wt. % 



% wurtzite % sphalerite 







 1-0 



0-3 

 1-4 



3 



days 



2* 



98 





100 

 75 



1-0 



_.__t 



4 



a 







100 





5 



2-0 



„_.f 



. 









100 









2-0 



1-1 



2 



a 



2 or 3 



97-98 





5 



2 



1-5 





a 







100 





10 



3*0 



1-9 





it 



50 



50 









5-0 



2-2 



i i 

 •■a 



(( 



50 



50 









8-0 



3-5 



H 



a 



99 



1 









8'0 



2-8 





a 



100 













8-0 



3-7 





a 



75 



25 









lO'O 



3-4 



2 



u 



100 













io-o 



3-3 



2 



a 



100 













lO'O 



3-7 



1 



a 



25 



75 









* This wurtzite consisted of only 2 or 3 minute pieces of detached crusts. 

 fNot determined. 



. 



