The only highly flammable member of this group is hydrogen sulfide. It poses a particular danger because of its relatively wide flammability limits. However, some other inorganic sulfides can heat spontaneously and even ignite if exposed to moisture.

Materials in this group are generally basic, some strongly so, and therefore incompatible with acids. Many of these compounds are reducing agents and therefore react vigorously with oxidizing agents, including inorganic oxoacids, organic peroxides, and epoxides. Simple salts of sulfides (such as sodium, potassium, and ammonium sulfide) react vigorously with acids to release hydrogen sulfide gas.

Many of the members of this group behave as strong bases. Therefore, direct dermal exposure by these materials may cause severe burns. However, some inorganic sulfides are so insoluble (for example, mercury(II) sulfide and cadmium sulfide) that they are not caustic. This property depends upon solubility. Hydrogen sulfide is a toxic gas that irritates the eyes and mucous membranes at concentrations of around 50 ppm (sensitivity varies considerably from person to person). Most of the symptoms of hydrogen sulfide poisoning are reversible if the victim is quickly exposed to fresh air. The gas causes death at concentrations of around 1,000 ppm.

These materials contain anionic sulfur atoms attached to atoms other than carbon or oxygen, especially metals or hydrogen. Hydrogen sulfide (H2S) is the only member of this group that is volatile, and it has a very unpleasant odor. However, the other members do not generally have a scent. Most are solids.

Ammonium hydrosulfide, sodium hydrosulfide, ammonium sulfide, antimony sulfide, arsenic sulfide, arsenic trisulfide, lead sulfide, hydrogen sulfide, mercuric sulfide, phosphorus heptasulfide, potassium sulfide, selenium disulfide, sodium sulfide.