Cobalt compounds are chemical substances that contain the element cobalt, which is a transition metal. These compounds can be found in various forms, including cobalt(II) chloride, cobalt(II) sulfate, and cobalt(III) oxide. They are often used in industrial applications, such as in batteries, pigments, and catalysts. Cobalt compounds are also important in biological systems, as cobalt is a key component of vitamin B12, which is essential for human health. However, some cobalt compounds can be toxic in high concentrations, making it important to handle them with care in both industrial and laboratory settings.