Boric Acid (500 g)
CAS Number: 10043-35-3
Synonyms: boracic acid; orthoboric acid
Molecular formula: H3BO3
Molecular weight: 61.83
Melting point: ~171°C 1
Boric acid volatizes in steam. When heated to 100°C, the solid loses water and is slowly converted into metaboric acid (HBO2); tetraboric acid (H2B4O7) is formed at 140°C and boron trioxide (B2O3) at higher temperatures.3 pKa = 9.23 at 25°C; DpK/DT = -0.008 4 Useful buffering range is pH 8.2-10.1.
Stability / Storage as Supplied Boric acid is a very stable dry solid at room temperature. It should be stable indefinitely, but should be evaluated for continued suitability in user application every three to five years.