Abstract
Boron oxide in boron nitride was determined by an acid-base titration and by a colorimetric method. The outline of the recommended procedure is as follows. The sample (1 g) is heated in dilute sulfuric acid (1/10 N, 5 ml) for 2 hours. After filtering the residue, the filtrate is divided into two parts. The total amount of boron oxide (A) is determined by the acid-base titration with mannitol, and the amount of ammonia (B) which is the decomposition product of boron nitride is determined by the colorimetric method with Nessler's reagent. The amount of boron oxide due to the decomposition of boron nitride (C) is estimated from (B). The content of boron oxide in the sample is obtained from the difference between (A) and (C). Determinations at 0.1 and 4% levels were illustrated.
