Dihydroxyaluminum Sodium Carbonate USP Grade

NaAl(OH)2CO3 -- 143.99
Aluminum, [carbonato(1-)-O]dihydroxy-, monosodium salt.
Sodium (T-4)-[carbonato(2-)-O,O′]dihydroxyaluminate(1-).
Sodium (carbonato)dihydroxyaluminate(1-) [539-68-4; 16482-55-6].
Dihydroxyaluminum Sodium Carbonate contains not less than 98.3 percent and not more than 107.9 percent of dihydroxyaluminum sodium carbonate (CH2AlNaO5), calculated on the dried basis.

Identification:
A 1-g portion, treated with 20 mL of 3 N hydrochloric acid, dissolves with effervescence, and the resulting solution responds to the tests for Aluminum and to the flame test for Sodium.
pH: between 9.9 and 10.2 in a suspension (1 in 25).
Acid-neutralizing capacity: not less than 75.0% of the expected mEq value, determined on about 425 mg of the undried material, accurately weighed, and calculated in relation to the results of the Assay. Each mg of NaAl(OH)2CO3 has an expected acid-neutralizing capacity of 0.0278 mEq.
Loss on drying: Dry it at 130 to constant weight: it loses not more than 14.5% of its weight.
Isopropyl alcohol: To pass the test: The limit is 1.0%.
Sodium content: To pass the test: between 15.2% and 16.8% is found.
Mercury: the limit is 1 ppm.
Assay: Not less than 98.3 percent and not more than 107.9 percent of dihydroxyaluminum sodium carbonate (CH2AlNaO5), calculated on the dried basis.