Potassium bis(trimethylsilyl)amide

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 pK_a of 26 (compare to lithium diisopropylamide, at 36).

Potassium bis(trimethylsilyl)amide

Names
Preferred IUPAC name Potassium 1,1,1-trimethyl-N-(trimethylsilyl)silanaminide
Other names Potassium hexamethyldisilazide
Identifiers
CAS Number	40949-94-8
3D model (JSmol)	Interactive image
Abbreviations	KHMDS
ChemSpider	21171158
ECHA InfoCard	100.115.605
PubChem CID	3251421
UN number	3263
CompTox Dashboard (EPA)	DTXSID00390655
InChI InChI=1S/C6H18NSi2.K/c1-8(2,3)7-9(4,5)6;/h1-6H3;/q-1;+1 Key: IUBQJLUDMLPAGT-UHFFFAOYSA-N
SMILES C[Si](C)(C)N([K])[Si](C)(C)C
Properties
Chemical formula	KSi 2C 6NH 18
Molar mass	199.4831 g mol^−1
Appearance	White, opaque crystals
Solubility in water	Reacts
Hazards
GHS pictograms
GHS Signal word	Danger
GHS hazard statements	H314[1]
GHS precautionary statements	P280, P305+351+338, P310[1]
Related compounds
Other cations	Lithium bis(trimethylsilyl)amide Sodium bis(trimethylsilyl)amide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Structure

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.[2]

See also

• Metal bis(trimethylsilyl)amides

References

1. Potassium bis(trimethylsilyl)amide, Sigma-Aldrich
2. Tesh, Kris F.; Hanusa, Timothy P.; Huffman, John C. (1990). "Ion pairing in [bis(trimethylsilyl)amido]potassium: The x-ray crystal structure of unsolvated [KN(SiMe3)2]2". Inorg. Chem. 29 (8): 1584–1586. doi:10.1021/ic00333a029.