The proper storage of chemicals has become a focal point of laboratory safety. We need to keep chemicals which are incompatible separated some reasonable distance from each other. At the same time, the law of diminishing returns applies here. One can expend a significant amount of energy and now receive much additional protection for the effort. Today, most chemical manufacturers have settled on a five color scheme for segregating chemicals. Red for flammables, blue for health hazards, yellow for oxidizers, white for corrosives, and a fifth color for less hazardous materials.

Within these categories some additional separation is recommended. Acids and bases need some separation. They would react violently if the two broke and mixed. Within the acids group, put the oxidizing acids (perchloric and nitric) off by themselves. Keep all flammables (solvents, fuels, etc.) separate from oxidizers (nitrates, perchlorates, azides, peroxides, etc.). Within each of the categories, chemicals can be arranged alphabetically.

Having said all this about segregation of chemicals, I would only add one final observation. Arrangement is last on my list of what's important for chemical storage.

#1 is security — keeping the door locked or access controlled.

#2 is having adequate space.

#3 is ventilation. I recommend one cubic foot of air per minute per square foot of floor space.

#4 is fire protection.

The worst way to discover a fire in the chemical storeroom is by opening the door (It happened in New Hampshire). Have an alarm system. Arrangement is last on my list.