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Naphthalene

Naphthalene
Skeletal formula and numbering system of naphthalene
Ball-and-stick model of naphthalene
Spacefill model of naphthalene
Unit cells of naphthalene
Names
Preferred IUPAC name
Naphthalene
Systematic IUPAC name
Bicyclo[4.4.0]deca-1,3,5,7,9-pentaene
Bicyclo[4.4.0]deca-2,4,6,8,10-pentaene
Other names
white tar, camphor tar, tar camphor, naphthalin, naphthaline, antimite, albocarbon, hexalene, mothballs, moth flakes
Identifiers
91-20-3 YesY
3D model (Jmol) Interactive image
1421310
ChEBI CHEBI:16482 YesY
ChEMBL ChEMBL16293 YesY
ChemSpider 906 YesY
ECHA InfoCard 100.001.863
EC Number 214-552-7
3347
KEGG C00829 YesY
PubChem 931
RTECS number QJ0525000
UNII 2166IN72UN N
Properties
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)
1.0253 g/cm3 (20 °C)
0.9625 g/cm3 (100 °C)
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
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)
Solubility Soluble in alcohols, liquid ammonia, carboxylic acids, C6H6, SO2,CCl4, CS2, toluene, aniline
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)
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)
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)
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)
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)
log P 3.34
Vapor pressure 8.64 Pa (20 °C)
23.6 Pa (30 °C)
0.93 kPa (80 °C)
2.5 kPa (100 °C)
0.42438 L·atm/mol
-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)
1.5898
Viscosity 0.964 cP (80 °C)
0.761 cP (100 °C)
0.217 cP (150 °C)
Structure
Monoclinic
P21/b
C5
2h
a = 8.235 Å, b = 6.003 Å, c = 8.658 Å
α = 90°, β = 122.92°, γ = 90°
Thermochemistry
165.72 J/mol·K
167.39 J/mol·K
78.53 kJ/mol
201.585 kJ/mol
-5156.3 kJ/mol
Hazards
Main hazards Flammable, , possible carcinogen. Dust can form explosive mixtures with air
GHS pictograms The flame pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS)The exclamation-mark pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS)The health hazard pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS)The environment pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS)
GHS signal word Danger
H228, H302, H351, H410
P210, P273, P281, P501
Harmful Xn Dangerous for the Environment (Nature) N
R-phrases R22, R40, R50/53
S-phrases (S2), S36/37, S46, S60, S61
NFPA 704
Flammability code 2: Must be moderately heated or exposed to relatively high ambient temperature before ignition can occur. Flash point between 38 and 93 °C (100 and 200 °F). E.g., diesel fuel Health code 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g., chloroform Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
Flash point 80 °C (176 °F; 353 K)
525 °C (977 °F; 798 K)
Explosive limits 5.9%
10 ppm (TWA), 15 ppm (STEL)
Lethal dose or concentration (LD, LC):
LD50 (median dose)
 1800 mg/kg (rat, oral)
490 mg/kg (rat, oral)
1200 mg/kg (guinea pig, oral)
533 mg/kg (mouse, oral)
US health exposure limits (NIOSH):
PEL (Permissible)
 TWA 10 ppm (50 mg/m3)
REL (Recommended)
 TWA 10 ppm (50 mg/m3) ST 15 ppm (75 mg/m3)
IDLH (Immediate danger)
 250 ppm
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N  (what is YesYN ?)
Infobox references

Naphthalene is an organic compound with formula C
10H
8. It is the simplest polycyclic aromatic hydrocarbon, and is a white crystalline solid with a characteristic odor that is detectable at concentrations as low as 0.08 ppm by mass. As an aromatic hydrocarbon, naphthalene's structure consists of a fused pair of benzene rings. It is best known as the main ingredient of traditional mothballs.

In the early 1820s, two separate reports described a white solid with a pungent odor derived from the distillation of coal tar. In 1821, John Kidd cited these two disclosures and then described many of this substance's properties and the means of its production. He proposed the name naphthaline, as it had been derived from a kind of naphtha (a broad term encompassing any volatile, flammable liquid hydrocarbon mixture, including coal tar). Naphthalene's chemical formula was determined by Michael Faraday in 1826. The structure of two fused benzene rings was proposed by Emil Erlenmeyer in 1866, and confirmed by Carl Gräbe three years later.

A naphthalene molecule can be viewed as the fusion of a pair of benzene rings. (In organic chemistry, rings are fused if they share two or more atoms.) As such, naphthalene is classified as a benzenoid polycyclic aromatic hydrocarbon (PAH). There are two sets of equivalent hydrogen atoms: the alpha positions are numbered 1, 4, 5, and 8 (per diagram in right margin), and the beta positions, 2, 3, 6, and 7.


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Wikipedia

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