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Names | |||
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Preferred IUPAC name
Naphthalene
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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 |
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Other names
white tar, camphor tar, tar camphor, naphthalin, naphthaline, antimite, albocarbon, hexalene, mothballs, moth flakes
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Identifiers | |||
91-20-3 | |||
3D model (Jmol) | Interactive image | ||
1421310 | |||
ChEBI | CHEBI:16482 | ||
ChEMBL | ChEMBL16293 | ||
ChemSpider | 906 | ||
ECHA InfoCard | 100.001.863 | ||
EC Number | 214-552-7 | ||
3347 | |||
KEGG | C00829 | ||
PubChem | 931 | ||
RTECS number | QJ0525000 | ||
UNII | 2166IN72UN | ||
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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) |
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Melting point | 78.2 °C (172.8 °F; 351.3 K) 80.26 °C (176.47 °F; 353.41 K) at 760 mmHg |
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Boiling point | 217.97 °C (424.35 °F; 491.12 K) at 760 mmHg |
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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) |
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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) |
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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) |
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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) |
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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) |
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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) |
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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) |
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Henry's law
constant (kH) |
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) |
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Refractive index (nD)
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1.5898 | ||
Viscosity | 0.964 cP (80 °C) 0.761 cP (100 °C) 0.217 cP (150 °C) |
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Structure | |||
Monoclinic | |||
P21/b | |||
C5 2h |
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a = 8.235 Å, b = 6.003 Å, c = 8.658 Å
α = 90°, β = 122.92°, γ = 90°
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Thermochemistry | |||
165.72 J/mol·K | |||
Std molar
entropy (S |
167.39 J/mol·K | ||
Std enthalpy of
formation (ΔfH |
78.53 kJ/mol | ||
Gibbs free energy (ΔfG˚)
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201.585 kJ/mol | ||
Std enthalpy of
combustion (ΔcH |
-5156.3 kJ/mol | ||
Hazards | |||
Main hazards | Flammable, , possible carcinogen. Dust can form explosive mixtures with air | ||
GHS pictograms | |||
GHS signal word | Danger | ||
H228, H302, H351, H410 | |||
P210, P273, P281, P501 | |||
EU classification (DSD)
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Xn N | ||
R-phrases | R22, R40, R50/53 | ||
S-phrases | (S2), S36/37, S46, S60, S61 | ||
NFPA 704 | |||
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)
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1800 mg/kg (rat, oral) 490 mg/kg (rat, oral) 1200 mg/kg (guinea pig, oral) 533 mg/kg (mouse, oral) |
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US health exposure limits (NIOSH): | |||
PEL (Permissible)
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TWA 10 ppm (50 mg/m3) | ||
REL (Recommended)
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TWA 10 ppm (50 mg/m3) ST 15 ppm (75 mg/m3) | ||
IDLH (Immediate danger)
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250 ppm | ||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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what is ?) | (|||
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.