Another portion (0.1876 gram substance) of the same barium inosite 

 hexaphosphate without previous drying gave 0.0022 gram Mg 2 P 2 7 

 after heating one hour with the ammonium molybdate, or 0.32 per 

 cent, in organic phosphorus ; after heating the solution one-half hour 

 more 0.0010 gram Mg,P,0 7 was obtained ; further heating for one hour 

 gave 0.0022 gram Mg,P 2 7 and a fourth hour's heating gave 0.0040 

 gram Mg 2 P,0 7 . 



The total inorganic phosphorus obtained after heating 3 ] 4 hours 

 as above was 1.39 per cent. The results indicate that the cleavage 

 under these conditions is slow and that it proceeds at a very uniform 

 rate. 



EXPERIMENT TO DETERMINE WHETHER INOSITE IS 



FORMED IN THE SPONTANEOUS DECOMPOSITION 



OF INOSITE HEXAPHOSPHORIC ACID 



The sample of old inosite hexaphosphoric acid previously referred 

 to was used. As shown by the analysis, the preparation contained 3.10 

 per cent, inorganic phosphorus. Of this acid, 12.8 grams (correspond- 

 ing to 10 grams of the dry substance) were dissolved in about 500 cc. 

 of water and barium hydroxide (Kahlbaum, alkali free) added to 

 slight alkaline reaction. The precipitate was filtered and washed sev- 

 eral times in water. The barium precipitate was reserved for special 

 examination. 



The filtrate was examined for inosite as follows : The excess of 

 barium hydroxide was precipitated with carbon dioxide filtered and 

 evaporated on the water-bath nearly to dryness. The residue was 

 taken up in a few cc. of hot water, filtered from a small amount of 

 barium carbonate and the nitrate mixed with alcohol and ether and 

 allowed to stand for several days in the ice chest. A trace of a white, 

 amorphous precipitate had separated, but absolutely no inosite crystals 

 appeared. 



In case the organic part of the inosite hexaphosphoric acid mole- 

 cule, corresponding to the inorganic phosphoric acid present, had sep- 

 arated as inosite, the above quantity, 10 grams, should have contained 

 about 0.3 grams of inosite and such a quantity could not have escaped 

 detection. Since no inosite could be isolated, it seems fair to assume 

 that under the above conditions of spontaneous decomposition inosite 

 hexaphosphoric acid does not decompose into inosite and phosphoric 

 acid, but phosphoric acid plus some unknown substance. 



EXAMINATION OF THE ABOVE BARIUM PRECIPITATE 



In the hope of throwing some light upon the nature of this un- 

 known substance, the barium precipitate obtained on the addition of 



55 



