Shock Sensitive Compounds

Highly energetic compounds require special handling and added precautions. Potentially reactive materials must be evaluated for their possible explosive character through careful review of the literature available. The following table lists examples of many materials or classes of compounds which have been found to be shock sensitive. Many are so sensitive that the mere scraping of a spatula on the side of the container is sufficient to initiate an explosion.

Materials Sensitive to Shock

acetylenic compounds, especially polyacetylenes, haloacetylenes, heavy metal salts
acyl nitrates
alkyl nitrates, especially nitrocellulose and nitroglycerine
alkyl and acyl nitrates
alkyl perchlorates
amminemetal oxosalts (metal compounds with coordinated ammonia or other nitrogenous donors and ionic perchlorate, nitrate, permanganate or other oxidizing group)
azides, including metal, nonmetal and organic azides
chlorite salts of metals, such as AgClO2 and Hg(ClO2)2
diazo compounds, such as CH2N2
fulminates
N-halogen compounds, such as difluoroamino compounds and halogen azides
perchlorate salts, most metal, nonmetal and amine perchlorates can be detonated and may undergo violent reaction when in contact with combustible materials
peroxides and hydroperoxides, organic
peroxides (crystallized) that have been formed from or are left from evaporation of peroxidizable solvents
peroxides, transition metal salts
picrates, especially salts of transition and heavy metals such as Ni, Pb, Hg, Cu and Zn; picric acid is explosive when dry
polynitroalkyl compounds, such as tetranitromethane and dinitroacetonitrile
polynitroaromatic compounds, especially polynitro hydrocarbons, phenols, amines (trinitrotoluene, trinitrobenzene)
N-nitro compounds, such as N-nitromethylamine, nitrourea, nitric amide

Organic Peroxides - An Especially Dangerous Class of Shock Sensitive Compounds

Organic peroxides are a special group of compounds with unusual stability and reactivity problems associated with them (NRC, Prudent Practices for Handling Hazardous Chemicals in the Laboratory). Chemicals in this class are perhaps the most hazardous materials that are handled routinely in the chemical lab. They may be characterized as low-power explosives, especially hazardous if exposed to shock, friction, sparks or other ignition sources. Many organic peroxides that are handled in the lab are more sensitive to shock than materials considered primary explosives, such as TNT.

These materials are sensitive to heat, friction, impact and light. All organic peroxides are extremely flammable, and fires in bulk storage of these materials, should be approached with extreme caution.

Special precautions are warranted for handling organic peroxides:

Maintain a minimum quantity of materials on hand. Never return unused portions to the container.
If the material is spilled, absorb it on vermiculite or other spill control material immediately.
The sensitivity of these materials to shock can be lessened by diluting with inert solvents such as aliphatic hydrocarbons. Do not use aromatic solvents such as toluene, since this has been shown to cause decomposition of certain members of this class.
Never increase the concentration of the peroxide through evaporation.
Never use metal spatulas because the metal may cause violent decomposition.
Keep all ignition sources away from organic peroxides.
Avoid all forms of friction, grinding and impact.

Created and maintained by Nancy Magnussen
last revised 2 Aug 1997
nancy@isc.tamu.edu