Hexamethyldisilazane

Hexamethyldisilazane (CAS 999-97-3), also known as (TMS)2NH, HMDS, or Hexamethyldisilylamine, is a silicon-nitrogen compound supplied as a high-purity reagent and surface treatment agent. It carries no assigned E-code and is registered under EC 213-668-5. It is commercially referenced under abbreviations including SILAZANE HMN and the shorthand formula ((CH3)3Si)2NH.

In personal care formulations, HMDS functions as a skin conditioner by forming a thin silicone film that reduces moisture loss and improves spreadability. In industrial surface modification, it reacts with hydroxyl groups on silica, glass, or metal oxide surfaces to introduce trimethylsilyl groups, rendering surfaces hydrophobic and improving compatibility with non-polar matrices. This silylation mechanism also makes it a reagent in chromatography column deactivation.

Hexamethyldisilazane is available in reagent and technical grades and is subject to REACH registration requirements within the EU. It is supplied in standard laboratory quantities through to drum volumes. Procurement teams should verify SDS compliance and confirm grade suitability against application-specific purity thresholds.