Bis(trimethylsilyl)amine

Bis(trimethylsilyl)amine

Names
Preferred IUPAC name 1,1,1-Trimethyl-N-(trimethylsilyl)silanamine
Other names Bis(trimethylsilyl)azane Bis(trimethylsilyl)amine 1,1,1,3,3,3-Hexamethyldisilazane (no longer recommended) Hexamethyldisilazane (ambiguous)
Identifiers
CAS Number	999-97-3 Y
3D model (JSmol)	Interactive image Interactive image
Abbreviations	HMDS
Beilstein Reference	635752
ChEBI	CHEBI:85068
ChemSpider	13238 Y
ECHA InfoCard	100.012.425
EC Number	213-668-5
MeSH	Hexamethylsilazane
PubChem CID	13838 18913873 amine 45051731 sodium 45051783 potassium
RTECS number	JM9230000
UN number	2924, 3286
InChI InChI=1S/C6H19NSi2/c1-8(2,3)7-9(4,5)6/h7H,1-6H3 Y Key: FFUAGWLWBBFQJT-UHFFFAOYSA-N Y InChI=1/C6H19NSi2/c1-8(2,3)7-9(4,5)6/h7H,1-6H3 Key: FFUAGWLWBBFQJT-UHFFFAOYAF
SMILES C[Si](C)(C)N[Si](C)(C)C N([Si](C)(C)C)[Si](C)(C)C
Properties
Chemical formula	C6H19NSi2
Molar mass	161.40 g·mol−1
Appearance	colorless liquid
Density	0.77 g cm−3
Melting point	−78 °C (−108 °F; 195 K)
Boiling point	126 °C (259 °F; 399 K)
Solubility in water	slow hydrolysis
Refractive index (nD)	1.4080
Hazards
Safety data sheet	External MSDS
NFPA 704	3 1 1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
(what is Y ?)
Infobox references

Bis(trimethylsilyl)amine (also known as hexamethyldisilazane, or HMDS) is an organosilicon compound with the molecular formula [(CH₃)₃Si]₂NH. The molecule is a derivative of ammonia with trimethylsilyl groups in place of two hydrogen atoms. This colorless liquid is a reagent and a precursor to bases that are popular in organic synthesis and organometallic chemistry.

Bis(trimethylsilyl)amine is prepared by treatment of trimethylsilyl chloride with ammonia:

The product is usually handled using air-free techniques since it hydrolyzes slowly in humid air.

Alkali metal bis(trimethylsilyl)amides result from the deprotonation of bis(trimethylsilyl)amine. For example, lithium bis(trimethylsilyl)amide (LiHMDS) is prepared using n-butyllithium:

Together with sodium bis(trimethylsilyl)amide (NaHMDS) and potassium bis(trimethylsilyl)amide (KHMDS), LiHMDS is used as a non-nucleophilic base.

One of the uses of HMDS is as a reagent in condensation reactions of heterocyclic compounds such as in the microwave synthesis of a derivative of xanthine:

HMDS can be used to convert alcohols into trimethylsilyl ethers. HMDS can be used to silylate laboratory glassware and make it hydrophobic, or automobile glass, just as Rain-X does.