Ferri-pyrophosphates

Hydrogen ferri-pyrophosphate, H6[Fe2(P207)3].7H20, results as a white solid when ferric pyrophosphate is heated for twelve hours at 50° C. with syrupy pyrophosphoric acid in acetone. 

Sodium ferro-pyrophosphate, NasFe2(P207)3, and sodium ferro- and ferri-metaphosphates, Na4Fe(P03)6 and Na3Fe(P03)6, have similarly been prepared.1... 

The ferri pyrophosphoH V. S.) is probably a mixture, or compound ( ) of ferric pyrophosphate, trisodic citrate, and ferric citrate. 

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