Forensic Chemistry: Explosives

A set of vocabularies related to forensic chemistry and explosives to aid in exam preparation.

Explosion

Rapid release of pressure and gas; may occur without detonation.

Combustion

Self-sustaining oxidation that proceeds by heat transfer; flame visible.

Deflagration

Subsonic flame front driven by thermal conductivity.

Detonation

Supersonic reaction front that compresses unreacted explosive via shock.

Pressure Wave

Wave generated by an explosion, characterized by sudden changes in pressure.

Brisance

Ability to shatter materials, proportional to detonation pressure.

Fragmentation

Casing breaks into high-velocity projectiles causing secondary injuries.

Thermal Effects

Incendiary heat ignites surroundings and burns victims.

ANFO

Ammonium Nitrate Fuel Oil; an explosive made from small granules soaked in fuel oil.

TNT

Trinitrotoluene; a melt-castable, insensitive secondary explosive.

RDX

Cyclonite; used in explosives like Composition C-4.

HMX

Octogen; higher performance than RDX, used in shaped charges.

IED

Improvised explosive device, often fabricated from dual-use chemicals.

Primary Explosives

Very sensitive explosives that need minimal stimuli to detonate.

Secondary Explosives

Require a booster or shaped detonation wave for initiation.

Single-Base Propellant

Propellant that contains only nitrocellulose; burns progressively.

Double-Base Propellant

Propellant consisting of nitrocellulose and nitroglycerin.

Nitroglycerin

A sensitive and powerful explosive liquid, used in dynamite.

Nitramines

Explosives with a basic structure of R–NH–NO₂; includes RDX and HMX.

Nitrate Esters

Explosives containing covalent -O-NO₂ functional groups; includes nitroglycerin.

Peroxide Explosives

Explosives formed from acid-catalyzed condensation with hydrogen peroxide.

Sensitivity Metrics

Measures such as impact, friction sensitivity, and thermal stability.

Power Index (PI)

Relative explosive power calculated from detonation characteristics.

Detonation Velocity (Dₙ)

Wave speed through explosive mass, critical for charge geometry.

Oxygen Balance (OB)

Determines the relative excess or deficit of oxygen in an explosive.

Improvised Explosives

Homemade explosives often made from common chemicals.

Ion Mobility Spectrometry (IMS)

Technique for detecting ions based on their mobility in a drift tube.

Remote Sensing

Stand-off detection methods for identifying explosives from a distance.

Gas Volume (V)

Total moles of gaseous products generated during an explosion.

Forensic Analysis

Scientific examination of explosive materials for legal purposes.

Laboratory Confirmation

Definitive identification of explosives through systematic analysis.

Spectroscopic Methods

Techniques like FTIR and Raman spectroscopy used for explosive detection.

Case Study

Application of analytical techniques to characterize explosive materials.

Safety Regulations

Guidelines for handling and storing explosives to ensure safety.