Cover Image

PAPERBACK
$63.25



View/Hide Left Panel

TABLE 6–1 Summary of Physical and Chemical Properties for Hydrogen Cyanide

Characteristic

Value

Molecular formula

HCN

Chemical structure

H—C≡N

Molecular weight

27.03

CAS number

74–90–8

Synonyms

Formonitrile, hydrocyanic acid, prussic acid

Physical state

Gas or liquid

Color

Colorless gas or bluish-white liquid

Odor

Bitter almond odor

Odor threshold

0.58 ppm

Low threshold, 0.9 ppm

High threshold, 5.0 ppm

Melting point

13.4°C

Boiling point

25.70°C

Solubility in water

Miscible

Vapor pressure

630 mm Hg at 20°C

807 mm Hg at 27°C

Vapor density (air=1)

0.941

Conversion factors

25°C, 1 atm

1 ppm=1.10 mg/m3

1 mg/m3=0.91 ppm

Abbreviations: CAS, Chemical Abstract Service.

Sources: Hartung 1994; Budavari et al. 1996; ATSDR 1997.

In 1993, an estimated total of 2.23 million pounds of hydrogen cyanide (approximately 73.1% of the total environmental release) was released into the air from U.S. industrial facilities (EPA 1995). Hydrogen cyanide also is released into the air from natural biogenic processes of plants, bacteria, and fungi; however, an estimate of that amount is not available (Cicerone and Zellner 1983; Crutzen and Carmichael 1993; Fiksel et al. 1981; Knowles 1988). Biomass burning could represent a significant source (1.1–3.7 billion pounds annually) of atmospheric hydrogen cyanide (Crutzen and Carmichael 1993; Lobert and Warnatz 1993). Lowry et al. (1985) detected hydrogen cyanide in 12% of the fires they studied in Dallas, Texas. In 10% of the fires in which hydrogen cyanide was



The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement