Urea

Urea
Names
Pronunciation	urea /jʊəˈriːə/, carbamide /ˈkɑːrbəmaɪd/
	Preferred IUPAC name Urea
	Systematic IUPAC name Carbonic diamide
	Other names Carbamide; Carbonyldiamide; Carbonyldiamine; Diaminomethanal; Diaminomethanone;
Identifiers
CAS Number	57-13-6 ;
3D model (JSmol)	Interactive image;
Beilstein Reference	635724
ChEBI	CHEBI:16199 ;
ChEMBL	ChEMBL985 ;
ChemSpider	1143 ;
DrugBank	DB03904 ;
ECHA InfoCard	100.000.286
E number	E927b (glazing agents, ...)
Gmelin Reference	1378
IUPHAR/BPS	4539;
KEGG	D00023 ;
PubChem CID	1176;
RTECS number	YR6250000;
UNII	8W8T17847W ;
CompTox Dashboard (EPA)	DTXSID4021426 ;
	InChI InChI=1S/CH4N2O/c2-1(3)4/h(H4,2,3,4) Key: XSQUKJJJFZCRTK-UHFFFAOYSA-N ; InChI=1/CH4N2O/c2-1(3)4/h(H4,2,3,4) Key: XSQUKJJJFZCRTK-UHFFFAOYAF;
	SMILES C(=O)(N)N;
Properties
Chemical formula	CO(NH2)2
Molar mass	60.06 g/mol
Appearance	White solid
Density	1.32 g/cm3
Melting point	133 to 135 °C (271 to 275 °F; 406 to 408 K)
Boiling point	decomposes
Solubility in water	545 g/L (at 25 °C)
Solubility	500 g/L glycerol 50 g/L ethanol; ~4 g/L acetonitrile
Basicity (pKb)	13.9
Conjugate acid	Uronium
Magnetic susceptibility (χ)	−33.4·10−6 cm3/mol
Structure
Dipole moment	4.56 D
ThermochemistryCRC Handbook
Std enthalpy of; formation (ΔfH⦵298)	−333.19 kJ/mol
Gibbs free energy (ΔfG⦵)	−197.15 kJ/mol
Pharmacology
ATC code	B05BC02 (WHO) D02AE01 (WHO)
Hazards
NFPA 704 (fire diamond)	1 1 0
Flash point	Non-flammable
	Lethal dose or concentration (LD, LC):
LD50 (median dose)	8500 mg/kg (oral, rat)
Safety data sheet (SDS)	ICSC 0595
Related compounds
Related ureas	Thiourea; Hydroxycarbamide
Related compounds	Carbamide peroxide; Urea phosphate; Acetone; Carbonic acid; Carbonyl fluoride;
	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

Urea, also called carbamide (because it is a diamide of carbonic acid), is an organic compound with chemical formula CO(NH₂)₂. This amide has two amino groups (–NH₂) joined by a carbonyl functional group (–C(=O)–). It is thus the simplest amide of carbamic acid.^[6]

Urea serves an important role in the cellular metabolism of nitrogen-containing compounds by animals and is the main nitrogen-containing substance in the urine of mammals. Urea is Neo-Latin, from French urée, from Ancient Greek οὖρον (oûron) 'urine', itself from Proto-Indo-European *h₂worsom.

It is a colorless, odorless solid, highly soluble in water, and practically non-toxic (LD₅₀ is 15 g/kg for rats).^[7] Dissolved in water, it is neither acidic nor alkaline. The body uses it in many processes, most notably nitrogen excretion. The liver forms it by combining two ammonia molecules (NH₃) with a carbon dioxide (CO₂) molecule in the urea cycle. Urea is widely used in fertilizers as a source of nitrogen (N) and is an important raw material for the chemical industry.

In 1828, Friedrich Wöhler discovered that urea can be produced from inorganic starting materials, which was an important conceptual milestone in chemistry. This showed for the first time that a substance previously known only as a byproduct of life could be synthesized in the laboratory without biological starting materials, thereby contradicting the widely held doctrine of vitalism, which stated that only living organisms could produce the chemicals of life.

^ ^a ^b Nomenclature of Organic Chemistry : IUPAC Recommendations and Preferred Names 2013 (Blue Book). Cambridge: The Royal Society of Chemistry. 2014. pp. 416, 860–861. doi:10.1039/9781849733069-FP001. ISBN 978-0-85404-182-4. The compound H₂N-CO-NH₂ has the retained name 'urea', which is the preferred IUPAC name, with locants N and N′, as shown above the structure below. The systematic name is 'carbonic diamide', (…).
^ Yalkowsky, Samuel H.; He, Yan; Jain, Parijat (19 April 2016). Handbook of Aqueous Solubility Data. CRC Press. ISBN 9781439802465.
^ "Solubility of Various Compounds in Glycerine" (PDF). msdssearch.dow.com. Archived from the original (PDF) on 13 April 2014. Retrieved 12 April 2014.
^ Loeser E, DelaCruz M, Madappalli V (9 June 2011). "Solubility of Urea in Acetonitrile–Water Mixtures and Liquid–Liquid Phase Separation of Urea-Saturated Acetonitrile–Water Mixtures". Journal of Chemical & Engineering Data. 56 (6): 2909–2913. doi:10.1021/je200122b.
^ Calculated from 14−pK_a. The value of pK_a is given as 0.10 by the CRC Handbook of Chemistry and Physics, 49th edition (1968–1969). A value of 0.18 is given by Williams, R. (24 October 2001). "pKa Data" (PDF). Archived from the original (PDF) on 24 August 2003.
^ "Carbamic acid".
^ "Urea - Registration Dossier - ECHA". echa.europa.eu.

[iupac2013-1] Nomenclature of Organic Chemistry : IUPAC Recommendations and Preferred Names 2013 (Blue Book). Cambridge: The Royal Society of Chemistry. 2014. pp. 416, 860–861. doi:10.1039/9781849733069-FP001. ISBN 978-0-85404-182-4. The compound H₂N-CO-NH₂ has the retained name 'urea', which is the preferred IUPAC name, with locants N and N′, as shown above the structure below. The systematic name is 'carbonic diamide', (…).

[Solubility-2] Yalkowsky, Samuel H.; He, Yan; Jain, Parijat (19 April 2016). Handbook of Aqueous Solubility Data. CRC Press. ISBN 9781439802465.

[3] "Solubility of Various Compounds in Glycerine" (PDF). msdssearch.dow.com. Archived from the original (PDF) on 13 April 2014. Retrieved 12 April 2014.

[4] Loeser E, DelaCruz M, Madappalli V (9 June 2011). "Solubility of Urea in Acetonitrile–Water Mixtures and Liquid–Liquid Phase Separation of Urea-Saturated Acetonitrile–Water Mixtures". Journal of Chemical & Engineering Data. 56 (6): 2909–2913. doi:10.1021/je200122b.

[pK-5] Calculated from 14−pK_a. The value of pK_a is given as 0.10 by the CRC Handbook of Chemistry and Physics, 49th edition (1968–1969). A value of 0.18 is given by Williams, R. (24 October 2001). "pKa Data" (PDF). Archived from the original (PDF) on 24 August 2003.

[6] "Carbamic acid".

[7] "Urea - Registration Dossier - ECHA". echa.europa.eu.

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