Potassium bis(trimethylsilyl)amide (commonly abbreviated as KHMDS, Potassium(K) HexaMethylDiSilazide) is the chemical compound with the formula ((CH3)3Si)2NK. It is a strong, non-nucleophilic base with an approximate pKa of 26 (compare to lithium diisopropylamide, at 36).
|Preferred IUPAC name
Potassium hexamethyldisilazide
3D model (JSmol)
CompTox Dashboard (EPA)
|Molar mass||199.4831 g mol−1|
|Appearance||White, opaque crystals|
|P280, P305+P351+P338, P310|
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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In the solid state, the unsolvated compound is dimeric, with two potassium and two nitrogen atoms forming a square. This compound is soluble in hydrocarbon solvents and conducts electricity poorly in solution and in the melt. This is attributed to very strong ion pairing.