TABLE 5.1 Examples of Compatible Storage Groups

A: Compatible Organic Bases





Benzyltrimethylammonium hydroxide

B: Compatible Pyrophoric & Water-Reactive Materials

Sodium borohydride

Benzoyl chloride

Zinc dust

Alkyl lithium solutions such as methyl lithium in tetrahydrofuran

Methanesulfonyl chloride

Lithium aluminum hydride

C: Compatible Inorganic Bases

Sodium hydroxide

Ammonium hydroxide

Lithium hydroxide

Cesium hydroxide

D: Compatible Organic Acids

Acetic acid

Citric acid

Maleic acid

Propionic acid

Benzoic acid

E: Compatible Oxidizers Including Peroxides

Nitric acid

Perchloric acid

Sodium hypochlorite

Hydrogen peroxide

3-Chloroperoxybenzoic acid

F: Compatible Inorganic Acids not Including Oxidizers or Combustibles

Hydrochloric acid

Sulfuric acid

Phosphoric acid

Hydrogen fluoride solution

J: Poison Compressed Gases

Sulfur dioxide


K: Compatible Explosives or Other Highly Unstable Materials

Picric acid dry(<10% H2O)



Urea nitrate

L: Nonreactive Flammables and Combustibles, Including Solvents





X: Incompatible with ALL Other Storage Groups

Picric acid moist (10-40% H2O)


Benzyl azide

Sodium hydrogen sulfide

NOTE: A larger list of examples can be found on the CD that accompanies this book.
SOURCE: Adapted from Stanford University’s Chem Tracker Storage System. Used with permission from Lawrence M. Gibbs, Stanford University.

     Some chemicals are regulated by federal agencies and require locked cabinets or storage in secure areas.

5.E.2 Storage According to Compatibility

It is prudent to store containers of incompatible chemicals separately. Separation of incompatibles will reduce the risk of mixing in case of accidental breakage, fire, earthquake, or response to a laboratory emergency. Even when containers are tightly closed, fugitive vapors can cause deleterious incompatibility reactions that degrade labels, shelves, cabinets, and containers themselves. As discussed in Chapter 4, a far more detailed review of incompatibilities needs to be done when chemicals are deliberately mixed,

Figure 5.1 (also available on the CD accompanying this book) and Table 5.1 show an example of a detailed classification system for the storage of groups of chemicals by compatibility. The system classifies chemicals into 11 storage groups. Each group should be separated by secondary containment (e.g., plastic trays) or, ideally, stored in its own storage cabinet. According to this system, it is most important to separate storage groups B (compatible pyrophoric and water-reactive chemicals) and X (incompatible with all other storage groups). These two groups merit their own storage cabinets. The accompanying compact disc includes a spreadsheet of hundreds of chemicals listed according to these storage groups.

There are other good classification systems for storing chemicals according to compatibility. At a minimum, always store fuels away from oxidizers. In other systems, the following chemical groups are kept separate by using secondary containment, cabinets, or distance:

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