Oxidizing agents are chemicals that bring about an oxidation reaction. The oxidizing agent may provide oxygen to the substance being oxidized (in which case the agent has to be oxygen or contain oxygen) or receive electrons being transferred from the substance undergoing oxidation (chlorine is a good oxidizing agent for electron-transfer purposes, even though it does not contain oxygen). The intensity of the oxidation reaction depends on the oxidizing-reducing potential of the material involved. Fire or explosion is possible when strong oxidizing agents come into contact with easily oxidizable compounds, such as metals, metal hydrides or organics. Because oxidizing agents possess varying degrees of instability, they can be explosively unpredictable.
| Gases | Fluorine, chlorine, ozone, nitrous oxide, oxygen |
| Liquids | Hydrogen peroxide, nitric acid, perchloric acid, bromine, sulphuric acid |
| Solids | Nitrites, nitrates, perchlorates, chromates, dichromates, picrates, permanganates, hypochlorites, bromates, iodates, chlorites, chlorates, persulphates. |
Explosives cause sudden, almost instantaneous release of pressure, gas, and heat when subjected to sudden adverse conditions. Heat, light, mechanical shock, detonation, and certain catalysts can initiate explosive reactions. Compounds containing the functional groups azide, acetylide, diazo, nitroso, haloamine, peroxide, and ozonide are sensitive to shock and heat and can explode violently.
Generally, organic peroxides are low-powered explosives that are sensitive to shock, sparks, and heat.
Some organic compounds such as ethers, tetrahydrofuran, and dioxan can react with oxygen from the air forming unstable peroxides. Peroxide formation can occur slowly under normal storage conditions -limited access to air and exposure to light. These accumulated peroxides can violently explode when exposed to shock, friction, or heat especially when concentrated and heated by distillation.
Bretherick (“Hazards in the Chemistry Laboratory”) points out the particular danger from peroxide formation by di-isopropyl ether.
These compounds react with water or moisture in the air releasing heat or flammable, toxic gas. Examples include alkali metals, alkaline earth metals, carbides, hydrides, inorganic chlorides, nitrides, peroxides, and phosphides.
Toxic gases may be evolved following the mixture of some chemicals e.g.
| Chemical A | Chemical B | Product |
| Arsenical materials | Any reducing agent | Arsine |
| Azides | Acids | Hydrogen Azide |
| Cyanides | Acids | Hydrogen Cyanide |
| Hypochlorites | Acids | Chlorine or hypochlorous acid |
| Nitrates | Sulphuric Acid | Nitrogen Dioxide |
| Nitric Acid | Copper, brass, any heavy metals | Nitrogen Dioxide |
| Nitrites | Acids | Nitrous fumes |
| Phosphorus | Caustic alkalis or reducing agents | Phosphine |
| Selenides | Reducing agents | Hydrogen Selenide |
| Sulphides | Acids | Hydrogen Sulphide |
| Tellurides | Reducing agents | Hydrogen Telluride |
Many chemicals may react violently on mixing accidentally or intentionally.
| Chemical | Incompatibles |
| Acetic acid | Chromic acid, nitric acid, hydroxyl compounds, ethylene glycol, perchloric acid, peroxides, permanganates |
| Acetylene | Chlorine, bromine, copper, fluorine, silver, mercury |
| Acetone | Concentrated nitric and sulphuric acid mixtures |
| Alkali and alkaline earth metals (such as powdered aluminium or magnesium, calcium, lithium, sodium, potassium) | Water, carbon tetrachloride or other chlorinated hydrocarbons, carbon dioxide, halogens |
| Ammonia (anhydrous) | Mercury (in manometers, for example), chlorine, calcium hypochlorite, iodine, bromine, hydrofluoric acid (anhydrous) |
| Ammonium nitrate | Acids, powdered metals, flammable liquids, chlorates, nitrites, sulphur, finely divided organic combustible materials |
| Aniline | Nitric acid, hydrogen peroxide |
| Arsenical materials | Any reducing agent |
| Azides | Acids |
| Bromine | See chlorine |
| Calcium oxide | Water |
| Carbon (activated) | Calcium hypochlorite, all oxidizing agents |
| Carbon tetrachloride | Sodium |
| Chlorates | Ammonium salts, acids, powdered metals, sulphur, finely divided organic or combustible materials |
| Chromic acid and chromium | Acetic acid, naphthalene, camphor, glycerol, alcohol, flammable liquids in general |
| Chlorine | Ammonia, acetylene, butadiene, butane, methane, propane (or other petroleum gases), hydrogen, sodium carbide, benzene, finely divided metals, turpentine |
| Chlorine dioxide | Ammonia, methane, phosphine, hydrogen sulphide |
| Copper | Acetylene, hydrogen peroxide |
| Cumene hydroperoxide | Acids (organic or inorganic) |
| Cyanides | Acids |
| Flammable liquids | Ammonium nitrate, chromic acid, hydrogen peroxide, nitric acid, sodium peroxide, halogens |
| Fluorine | All other chemicals |
| Hydrocarbons (such as butane, propane, benzene) | Fluorine, chlorine, bromine, chromic acid, sodium peroxide |
| Hydrocyanic acid | Nitric acid, alkali |
| Hydrofluoric acid (anhydrous) | Ammonia (aqueous or anhydrous) |
| Hydrogen peroxide | Copper, chromium, iron, most metals or their salts, alcohols, acetone, organic materials, aniline, nitromethane, combustible materials |
| Hydrogen sulphide | Fuming nitric acid, oxidizing gases |
| Hypochlorites | Acids, activated carbon |
| Iodine | Acetylene, ammonia (aqueous or anhydrous), hydrogen |
| Mercury | Acetylene, fulminic acid, ammonia |
| Nitrates | Sulphuric acid |
| Nitric acid (concentrated) | Acetic acid, aniline, chromic acid, hydrocyanic acid, hydrogen sulphide, flammable liquids, flammable gases, copper, brass, any heavy metals |
| Nitrites | Acids |
| Nitroparaffins | inorganic bases, amines |
| Oxalic acid | Silver, mercury |
| Oxygen | Oils, grease, hydrogen: flammable liquids, solids or gases |
| Perchloric acid | Acetic anhydride, bismuth and its alloys, alcohol, paper, wood, grease, oils |
| Peroxides, organic | Acids (organic or mineral), avoid friction, store cold |
| Phosphorus (white) | Air, oxygen, alkalis, reducing agents |
| Potassium | Carbon tetrachloride, carbon dioxide, water |
| Potassium chlorate | Sulphuric and other acids |
| Potassium perchlorate (see also chlorates) | Sulphuric and other acids |
| Potassium permanganate | Glycerol, ethylene glycol, benzaldehyde, sulphuric acid |
| Selenides | Reducing agents |
| Silver | Acetylene, oxalic acid, tartaric acid, ammonium compounds, fulminic acid |
| Sodium | Carbon tetrachloride, carbon dioxide, water |
| Sodium nitrite | Ammonium nitrate and other ammonium salts |
| Sodium peroxide | Ethyl or methyl alcohol, glacial acetic acid, acetic anhydride, benzaldehyde, carbon disulfide, glycerin, ethylene glycol, ethyl acetate, methyl acetate, furfural |
| Sulphides | Acids |
| Sulphuric acid | Potassium chlorate, potassium perchlorate, potassium permanganate (similar compounds of light metals, such as sodium, lithium) |
| Tellurides | Reducing agents |