THE CODEX AND THE BRITISH PIIA RMACOPCEIA. 
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CHAPTER XII. 
PHOSPHATES, PYROPHOSPHATES, ARSERIATES, AND ARSENITES. 
Of these there are nine, namely, phosphate of lime, phosphate of iron, crystals 
of phosphate of soda, crystals of pyrophosphate of soda, citro-ammoniacal pyro¬ 
phosphate of iron, arseniate of soda, Pearson’s arsenical solution, or solution of 
arseniate of soda in water, crystals of arseniate of pg^ash or arsenical salt of 
Macquer, solution of arsenite of potash or Fowler’s solution. 
111. Pyrophosphate de Fee Citeo-Ammoniacal. 
Fyrophosphas Ferricus cum Citrate Ammonico. 
Solution of perchloride of iron, No. 70 . One hundred and fifty-six grammes, 156. 
Crystals of pyrophosphate of soda . . . Eighty-four grammes.84. 
Citric acid. .... Twenty-six grammes . . . . . 26. 
Ammonia. q.s. 
Dissolve the pyrophosphate of soda in as much water as may be necessary, and 
by degrees pour the solution into the perchloride of iron, previously diluted with 
water, and wash the insoluble pyrophosphate ; on the other hand, dissolve the 
citric acid in a small quantity of water, and add to it sufficient ammonia to 
form a citrate with an excess of alkali. Turn the pyrophosphate of iron into 
this liquid, it will dissolve there, giving a yellowish solution ; concentrate this 
by gentle heat until it acquires a syrupy consistence, spread it upon plates or 
sheets of glass with a brush and dry in a stove. 
The salt obtained is the citro-ammoniacal pyrophosphate of iron, it is in the 
form of yellowish-brown scales, soluble in water, almost tasteless, and contain¬ 
ing about 18 per cent, of iron. The P. B. does not recognise this preparation. 
112. Arseniate de Soude*. 
2Na0,H0,As0 5 + 14H0 = 312. 
Arsenias Sodicus. 
Arseniate of Soda. Sodic Arseniate. 
Nitrate of soda.Two hundred grammes .... 200. 
Arsenious acid.One hundred and sixteen grammes, 116. 
Mix thoroughly the two substances; give them a red heat in a Hessian cruci¬ 
ble; treat the residue with water, pour into the liquor a solution of carbonate of 
soda, until it has a decidedly alkaline reaction ; let it evaporate, that crystals 
may form on cooling. 
If the mother-liquors are not alkaline, add a fresh quantity of carbonate of 
soda so as to obtain more crystals. Arseniate of soda in crystals gives an alka¬ 
line reaction. One hundred parts of the salt contain 36-85 of arsenic acid, and 
represent 24-03 of metallic arsenic. 
In the P. B. the dry powders of arsenious acid, nitrate of soda, and carbonate 
of soda are to be thoroughly mixed, then exposed to a full red heat till all 
effervescence has ceased, and complete fusion taken place. The solidified fused 
mass, whilst still warm, is to be dissolved in boiling water, then filtered and set 
aside to crystallize. In the Codex the filtering is omitted, which would seem 
to be an oversight. 
CHAPTER XIII. 
CARBONATES. BICARBONATES. 
The carbonates of manganese, lime, and soda, with the bicarbonates of potash 
and soda, make up the contents of this chapter. 
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