Manganese as the Pyrophosphate. 



237 



manganese to the ammonium manganese salt under the given 

 conditions. It is plain, moreover, that the assumption of a 

 crystalline condition can not serve as an indication that the 

 composition of the salt is ideal. It is to be noted, however, 

 that the conditions obtaining here are essentially different from 

 those in common practice ; for, ordinarily, when manganese is 

 to be determined ammonium salts are abundantly present as 

 the result of previous steps in analysis. 









Table 



II. 











Mn 2 P 2 7 equiva- 

 lant to the MnCl 2 



Taken. Found, 

 grm grm. 



Error in 



terms of 



Mn 2 P 2 7 . 



grm. 



Error in 



terms of 



Manganese. 



grm. 



Saturated 



solution of 



HN T aS£l 4 P0 4 



4H 2 0. 



cm :| . 



A 



NH 4 C1. 

 grm. 



Total 

 vol. 

 cm 3 . 



Time of 



standing 



cold. 



lirs. 



Mangan- 

 ese in the 

 filtrate. 



0-1542 



0-1520 



0-0022 — 



0-0008 — 



A. 



5 



5 



200 



15 



none 



0-1542 



01540 



0-0002- 



o-oooo — 





5 



10 



200 



15 



u 



0-1542 



0-1536 



00006 — 



00002 — 





5 



10 



100 



5 



a 



0-1542 



0-1535 



0-0007 — 



0-0002 — 





5 



20 



200 



2^ 



a 



0-3770 



0-3712 



0-0058 — 



0022 — 





5 



20 



200 



\ 



(< 



0-3770 



0-3724 



0-0046 — 



001S — 





5 



20 



200 



4 



u 



0-3084 



3069 



0015 — 



0-0006 — 





5 



40 



200 



1 



tc 



0-3084 



03060 



0-0024 — 



0-0009 — 





5 



4<> 



200 



1 



a 



0-3084 



0-3059 



0-0025 — 



0009 — 





5 



40 



200 



15 



trace 



0-3084 



0-3057 



0-0027 — 



00010 — 





5 



60 



200 



15 



none 



0-1542 



01521 



0-0021 — 



0-0008 — 



B 



5 



10 



100 



40 



none 



0-1542 



01512 



0-0030 — 



00010 — 





5 



10 



200 



40 



tt 



0-1542 



0-1532 



o-ooio — 



0-000 5 — 





5 



20 



200 



15 



tc 



0-1542 



01531 



o-oou — 



0-00)4 — 





5 



20 



100 



15 



a 



0-3770 



0-3720 



0-0050 — 



0-0019 — 





5 



20 



200 



-I 



a 



0*3770 



03745 



00035 — 



0-0014 — 





5 



20 



200 



\ 



a 



0-1542 



0-1519 



0-0023 — 



0-0009 — 



C. 



5 



15 



200 





none 



0-1542 



0-1530 



0-0012 — 



0-0004 — 





5 



20 



200 





u 



0-1512 



0*1525 



0-0017 — 



0007 — 





5 



30 



200 





(( 



0-3084 



0-3020 



0-0064 — 



00025 — 





5 



10 



200 





(I 



0-3084 



03053 



0-0031 — 



0-0012 — 





5 



20 



200 





cc 



0-3084 



3033 



0-0051 — 



0-0020 — 





5 



20 



200 





a 



0-3084 



0-3039 



00045 — 



0017 — 





5 



60 



200 



_. 



trace 



In the experiments of the next series the conditions are varied 

 simply in this respect, that ammonium salts are introduced 

 before the precipitation. The precipitate was less granular and 

 more silky. After ignition the mass was white with a faint rose 

 color. In the experiments of section A of the table the preci- 



