Barium is an alkaline earth metal element, the sixth periodic element of IIA group in the periodic table, and also an active element in alkaline earth metals.

Like other alkaline earth metals, barium is distributed everywhere on the earth: the content in the upper crust is 0.026%, while the average value in the crust is 0.022%. Barium mainly exists in the form of barite and exists in the form of sulfate or carbonate.

Barium is not an essential element for human body, but a toxic element. Eating soluble barium compounds can cause barium poisoning. Suppose the average weight of an adult is 70kg, and the total amount of barium in his body is about 16mg. After taking barium salt by mistake, it will be dissolved by water and gastric acid, leading to many poisoning incidents and some deaths.