Maleic acid

Maleic acid
Names
	Preferred IUPAC name (2Z)-But-2-enedioic acid
	Other names (Z)-Butenedioic acid; cis-Butenedioic acid; Malenic acid; Maleinic acid; Toxilic acid
Identifiers
CAS Number	110-16-7 ;
3D model (JSmol)	Interactive image;
Beilstein Reference	605762
ChEBI	CHEBI:18300 ;
ChEMBL	ChEMBL539648 ;
ChemSpider	392248 ;
DrugBank	DB04299;
ECHA InfoCard	100.003.403
EC Number	203-742-5;
Gmelin Reference	49854
KEGG	C01384 ;
PubChem CID	444266;
RTECS number	OM9625000;
UNII	91XW058U2C ;
CompTox Dashboard (EPA)	DTXSID8021517 ;
	InChI InChI=1S/C4H4O4/c5-3(6)1-2-4(7)8/h1-2H,(H,5,6)(H,7,8)/b2-1- Key: VZCYOOQTPOCHFL-UPHRSURJSA-N ; InChI=1/C4H4O4/c5-3(6)1-2-4(7)8/h1-2H,(H,5,6)(H,7,8)/b2-1- Key: VZCYOOQTPOCHFL-UPHRSURJBG;
	SMILES O=C(O)\C=C/C(=O)O;
Properties
Chemical formula	C4H4O4
Molar mass	116.072 g·mol−1
Appearance	White solid
Density	1.59 g/cm3
Melting point	135 °C (275 °F; 408 K) (decomposes)
Solubility in water	478.8 g/L at 20 C
Acidity (pKa)	pka1 = 1.90; pka2 = 6.07
Magnetic susceptibility (χ)	−49.71·10−6 cm3/mol
Hazards
	GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H302, H315, H317, H319, H335
Precautionary statements	P261, P264, P270, P271, P272, P280, P301+P312, P302+P352, P304+P340, P305+P351+P338, P312, P321, P330, P332+P313, P333+P313, P337+P313, P362, P363, P403+P233, P405, P501
NFPA 704 (fire diamond)	3 0 0
Safety data sheet (SDS)	MSDS from J. T. Baker
Related compounds
Related carboxylic acids	fumaric acid; succinic acid; crotonic acid
Related compounds	maleic anhydride; maleimide
	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

Maleic acid or cis-butenedioic acid is an organic compound that is a dicarboxylic acid, a molecule with two carboxyl groups. Its chemical formula is HO₂CCH=CHCO₂H. Maleic acid is the cis isomer of butenedioic acid, whereas fumaric acid is the trans isomer. Maleic acid is mainly used as a precursor to fumaric acid, and relative to its parent maleic anhydride, which has many applications.

Names




Preferred IUPAC name (2Z)-But-2-enedioic acid
Other names (Z)-Butenedioic acid; cis-Butenedioic acid; Malenic acid; Maleinic acid; Toxilic acid
Identifiers
CAS Number	110-16-7^Y
3D model (JSmol)	Interactive image
Beilstein Reference	605762
ChEBI	CHEBI:18300^Y
ChEMBL	ChEMBL539648^Y
ChemSpider	392248^Y
DrugBank	DB04299
ECHA InfoCard	100.003.403
EC Number	203-742-5
Gmelin Reference	49854
KEGG	C01384^Y
PubChem CID	444266
RTECS number	OM9625000
UNII	91XW058U2C^Y
CompTox Dashboard (EPA)	DTXSID8021517
InChI InChI=1S/C4H4O4/c5-3(6)1-2-4(7)8/h1-2H,(H,5,6)(H,7,8)/b2-1-^Y Key: VZCYOOQTPOCHFL-UPHRSURJSA-N^Y InChI=1/C4H4O4/c5-3(6)1-2-4(7)8/h1-2H,(H,5,6)(H,7,8)/b2-1- Key: VZCYOOQTPOCHFL-UPHRSURJBG
SMILES O=C(O)\C=C/C(=O)O
Properties
Chemical formula	C₄H₄O₄
Molar mass	116.072 g·mol⁻¹
Appearance	White solid
Density	1.59 g/cm³
Melting point	135 °C (275 °F; 408 K) (decomposes)
Solubility in water	478.8 g/L at 20 C
Acidity (pK_a)	pk_a1 = 1.90 pk_a2 = 6.07
Magnetic susceptibility (χ)	−49.71·10⁻⁶ cm³/mol
Hazards
GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H302, H315, H317, H319, H335
Precautionary statements	P261, P264, P270, P271, P272, P280, P301+P312, P302+P352, P304+P340, P305+P351+P338, P312, P321, P330, P332+P313, P333+P313, P337+P313, P362, P363, P403+P233, P405, P501
NFPA 704 (fire diamond)	3 0 0
Safety data sheet (SDS)	MSDS from J. T. Baker
Related compounds
Related carboxylic acids	fumaric acid succinic acid crotonic acid
Related compounds	maleic anhydride maleimide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Y verify (what is ^YN ?) Infobox references