Sulfamate

Sulfamic acid

Names
IUPAC name Sulfamic acid
Identifiers
CAS Number	5329-14-6 Y
3D model (JSmol)	Interactive image
ChEBI	CHEBI:9330 Y
ChemSpider	5767 Y
ECHA InfoCard	100.023.835
EC Number	226-218-8
PubChem CID	5987
RTECS number	WO5950000
UN number	2967
InChI InChI=1S/H3NO3S/c1-5(2,3)4/h(H3,1,2,3,4) Y Key: IIACRCGMVDHOTQ-UHFFFAOYSA-N Y InChI=1/H3NO3S/c1-5(2,3)4/h(H3,1,2,3,4) Key: IIACRCGMVDHOTQ-UHFFFAOYAK
SMILES O=S(=O)(O)N
Properties
Chemical formula	H3NSO3
Molar mass	97.10 g/mol
Appearance	white crystals
Density	2.15 g/cm3
Melting point	205 °C (401 °F; 478 K) decomposes
Solubility in water	Moderate, with slow hydrolysis
Solubility	Moderately soluble in DMF, Slightly soluble in MeOH, Insoluble in hydrocarbons
Acidity (pKa)	1.0
Hazards
Safety data sheet	ICSC 0328
EU classification (DSD) (outdated)	Irritant (Xi)
R-phrases (outdated)	R36/38 R52/53
S-phrases (outdated)	(S2) S26 S28 S61
Related compounds
Other cations	Ammonium sulfamate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Y  (what is YN ?)
Infobox references

Sulfamic acid, also known as amidosulfonic acid, amidosulfuric acid, aminosulfonic acid, and sulfamidic acid, is a molecular compound with the formula H₃NSO₃. This colorless, water-soluble compound finds many applications. Sulfamic acid melts at 205 °C before decomposing at higher temperatures to H₂O, SO₃, SO₂, and N₂.

Sulfamic acid (H₃NSO₃) may be considered an intermediate compound between sulfuric acid (H₂SO₄), and sulfamide (H₄N₂SO₂), effectively replacing an –OH group with an –NH₂ group at each step. This pattern can extend no further in either direction without breaking down the –SO₂ group. Sulfamates are derivatives of sulfamic acid.

Sulfamic acid is produced industrially by treating urea with a mixture of sulfur trioxide and sulfuric acid (or oleum). The conversion is conducted in two stages:

In this way, approximately 96,000 tons were produced in 1995.

The compound is well described by the formula H₃NSO₃, not the tautomer H₂NSO₂(OH). The relevant bond distances are S=O, 1.44 and S–N 1.77 Å. The greater length of the S–N distance is consistent with a single bond. Furthermore, a neutron diffraction study located the hydrogen atoms, all three of which are 1.03 Å distant from nitrogen. In the solid state, the molecule of sulfamic acid is well described by a zwitterionic form :

Water solutions are unstable and slowly hydrolyze to ammonium bisulfate, but the crystalline solid is indefinitely stable under ordinary storage conditions. Its behavior resembles that of urea, (H₂N)₂CO. Both feature amino groups linked to electron-withdrawing centers that can participate in delocalized bonding. Both liberate ammonia upon heating in water.