Sodium metaborate NaBO

Sodium perborate tnhydrate, NaBO 3H2O or Na2B2(02)2(0H)4 4H2O, triclinic, contains 11.8 wt % active oxygen (96). It has been claimed to have better thermal stabiUty than the tetrahydrate but has not been used commercially. The tnhydrate can be made by dehydration of the tetrahydrate or by crystallization from a sodium metaborate and hydrogen peroxide solution in the present of tnhydrate seeds. Between 18 and 50°C the tnhydrate is more stable but slower to crystallize than the tetrahydrate. Below 15°C the tnhydrate is spontaneously converted into the tetrahydrate. 

B 13.22%, Na 28.10%, O 58.68%. NaBO,. Contains, when reasonably fresh, about 95% of the perborate corresp to 9.9% available oxygen. Prepn from sodium metaborate and hydrogen peroxide Leblon, Lambert, U.S. pat. 3,109,706... 

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