By Allan Robinson
Updated Mar 24, 2022
Pure sodium perborate (NaBO₃) is a white, odorless solid that typically crystallizes with 1, 2, or 4 water molecules. The commercially relevant hydrates—monohydrate (NaBO₃·H₂O) and tetrahydrate (NaBO₃·4H₂O)—are prized for their stability and safety compared with similar bleaching agents such as sodium percarbonate or sodium perphosphate.
The tetrahydrate is synthesized from disodium tetraborate pentahydrate, hydrogen peroxide, and sodium hydroxide. It is less soluble than the monohydrate and less thermally stable. Heating the tetrahydrate yields the monohydrate, which offers superior solubility and is the preferred form for most commercial applications.
Sodium perborate is a key active ingredient in many tooth‑whitening products. In internal bleaching procedures, a controlled preparation of the compound is placed inside a non‑vital tooth; it gradually releases oxygen to lighten enamel from within while also providing antiseptic and disinfectant properties.
As an oxygen donor, sodium perborate enhances the effectiveness of laundry detergents and bleaches. It liberates clean, odor‑free oxygen that helps remove stains without the harshness associated with chlorine‑based agents.
Compared to sodium hypochlorite, sodium perborate causes less fading in colored fabrics. However, its oxygen release at temperatures below 60 °C requires an activator such as tetraacetylethylenediamine (TAED) to achieve rapid and efficient bleaching.
Formulated eye drops containing sodium perborate inhibit bacterial growth while remaining safe for ocular tissues, making it a valuable ingredient in sterile, antimicrobial ophthalmic solutions.
Overall, sodium perborate offers a safe, effective, and versatile bleaching and antimicrobial solution across a range of industries.
