Naphthalene

Not to be confused with naphtha or naphthene.

Naphthalene is a crystalline, white hydrocarbon, with a strong smell. It is best known as the main ingredient in mothballs, urinal deodorizer blocks, and can be used as an antiseptic. In mothballs, it is used as an insecticide or pesticide.

Naphthalene

Skeletal formula and numbering system of naphthalene Ball-and-stick model of naphthalene
Names
Preferred IUPAC name Naphthalene[1]
Systematic IUPAC name Bicyclo[4.4.0]deca-1,3,5,7,9-pentaene
Other names white tar, camphor tar, tar camphor, naphthalin, naphthaline, antimite, albocarbon, hexalene, mothballs, moth flakes
Identifiers
CAS Number	91-20-3 Y
3D model (JSmol)	Interactive image
Beilstein Reference	1421310
ChEBI	CHEBI:16482 Y
ChEMBL	ChEMBL16293 Y
ChemSpider	906 Y
ECHA InfoCard	100.001.863
EC Number	214-552-7
Gmelin Reference	3347
KEGG	C00829 Y
PubChem CID	931
RTECS number	QJ0525000
UNII	2166IN72UN N
CompTox Dashboard (EPA)	DTXSID8020913
SMILES c1ccc2ccccc2c1
Properties
Chemical formula	C10H8
Molar mass	128.17 g·mol−1
Appearance	White solid crystals/ flakes
Odor	Strong odor of coal tar
Density	1.145 g/cm3 (15.5 °C)[2] 1.0253 g/cm3 (20 °C) 0.9625 g/cm3 (100 °C)[2]
Melting point	78.2 °C (172.8 °F; 351.3 K) 80.26 °C (176.47 °F; 353.41 K) at 760 mmHg
Boiling point	217.97 °C (424.35 °F; 491.12 K) at 760 mmHg[2]
Solubility in water	19 mg/L (10 °C) 31.6 mg/L (25 °C) 43.9 mg/L (34.5 °C) 80.9 mg/L (50 °C)> 238.1 mg/L (73.4 °C)[3]
Solubility	Soluble in alcohols, liquid ammonia, carboxylic acids, C6H6, SO2,[3] CCl4, CS2, toluene, aniline[4]
Solubility in ethanol	5 g/100 g (0 °C) 11.3 g/100 g (25 °C) 19.5 g/100 g (40 °C) 179 g/100 g (70 °C)[4]
Solubility in acetic acid	6.8 g/100 g (6.75 °C) 13.1 g/100 g (21.5 °C) 31.1 g/100 g (42.5 °C) 111 g/100 g (60 °C)[4]
Solubility in chloroform	19.5 g/100 g (0 °C) 35.5 g/100 g (25 °C) 49.5 g/100 g (40 °C) 87.2 g/100 g (70 °C)[4]
Solubility in hexane	5.5 g/100 g (0 °C) 17.5 g/100 g (25 °C) 30.8 g/100 g (40 °C) 78.8 g/100 g (70 °C)[4]
Solubility in butyric acid	13.6 g/100 g (6.75 °C) 22.1 g/100 g (21.5 °C) 131.6 g/100 g (60 °C)[4]
log P	3.34
Vapor pressure	8.64 Pa (20 °C) 23.6 Pa (30 °C) 0.93 kPa (80 °C)[3] 2.5 kPa (100 °C)[5]
kH	0.42438 L·atm/mol
Magnetic susceptibility (χ)	-91.9·10−6 cm3/mol
Thermal conductivity	98 kPa: 0.1219 W/m·K (372.22 K) 0.1174 W/m·K (400.22 K) 0.1152 W/m·K (418.37 K) 0.1052 W/m·K (479.72 K)[6]
Refractive index (nD)	1.5898
Viscosity	0.964 cP (80 °C) 0.761 cP (100 °C) 0.217 cP (150 °C)[7]
Structure
Crystal structure	Monoclinic[8]
Space group	P21/b[8]
Point group	C5 2h[8]
Lattice constant	a = 8.235 Å , b = 6.003 Å , c = 8.658 Å[8] α = 90°, β = 122.92°, γ = 90°
Thermochemistry
Std enthalpy of formation ΔfHo298	78.53 kJ/mol
Std enthalpy of combustion ΔcHo298	-5156.3 kJ/mol
Standard molar entropy So298	167.39 J/mol·K[5]
Specific heat capacity, C	165.72 J/mol·K
Hazards
Main hazards	Flammable, sensitizer, possible carcinogen. Dust can form explosive mixtures with air
NFPA 704	2 2 0
Explosive limits	5.9%
U.S. Permissible exposure limit (PEL)	TWA 10 ppm (50 mg/m3)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YN ?)
Infobox references

Naphthalene is toxic. In humans, being exposed to naphthalene can destroy red blood cells. Naphthalene may also cause cancer.

History

In the early 1820s, two different papers were published on something that matched the description of Naphthalene. Both groups made it by distilling coal tar. In 1821 John Kidd cited both reports, and condensed their results to accurately describe the properties of naphthalene, and how to make it. Kidd named it naphthalene because "naphtha" means any explosive hydrocarbon mixture. By 1826, Michael Faraday discovered the formula for it. Emil Erlenmeyer proposes that it is two fused benzene rings in 1866, and Carl Gräbe confirms this three years later.