Tetramethylammonium hydroxide

Tetramethylammonium hydroxide
Names
	IUPAC name N,N,N-Trimethylmethanaminium hydroxide
	Other names tetramethylammonium hydroxide
Identifiers
CAS Number	75-59-2 ; 10424-66-5 (trihydrate) ; 10424-65-4 (pentahydrate) ;
3D model (JSmol)	Interactive image;
ChemSpider	54928 ;
ECHA InfoCard	100.000.803
PubChem CID	60966;
UNII	5GKP7317Q2 ; B2HKT2LCKQ (pentahydrate) ;
CompTox Dashboard (EPA)	DTXSID3029108 ;
	InChI InChI=1S/C4H12N.H2O/c1-5(2,3)4;/h1-4H3;1H2/q+1;/p-1 Key: WGTYBPLFGIVFAS-UHFFFAOYSA-M ; InChI=1/C4H12N.H2O/c1-5(2,3)4;/h1-4H3;1H2/q+1;/p-1 Key: WGTYBPLFGIVFAS-REWHXWOFAQ;
	SMILES C[N+](C)(C)C.[OH-];
Properties
Chemical formula	C4H13NO
Molar mass	91.154 g·mol−1
Density	~ 1.015 g/cm3 (20-25% aqueous solution)
Melting point	67 °C (153 °F; 340 K) (pentahydrate)
Boiling point	decomposes
Solubility in water	high
Hazards
	GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H300+H310, H314, H370, H372, H411
Precautionary statements	P260, P273, P280, P303+P361+P353, P304+P340+P310, P305+P351+P338
NFPA 704 (fire diamond)	3 0 0
Safety data sheet (SDS)	Sigma-Aldrich MSDS for TMAH·5H2O
Related compounds
Other anions	tetramethylammonium chloride
Other cations	tetraethylammonium hydroxide
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

Tetramethylammonium hydroxide (TMAH or TMAOH) is a quaternary ammonium salt with molecular formula N(CH₃)₄⁺ OH⁻. It is commonly encountered in form of concentrated solutions in water or methanol. TMAH in solid state and its aqueous solutions are all colorless, but may be yellowish if impure. Although TMAH has virtually no odor when pure, samples often have a strong fishy smell due to presence of trimethylamine which is a common impurity. TMAH has several diverse industrial and research applications.