锕系 (Actinides) is a series of 15 chemical elements in the periodic table, ranging from 锕 (Actinium, atomic number 89) to 锿 (Lawrencium, atomic number 103). These elements are known for their radioactive properties and are typically found in nature in trace amounts. They are primarily used in nuclear energy and weapons, as well as in various scientific applications. The actinides are characterized by their similar properties, including the ability to form complex compounds and their tendency to exhibit multiple oxidation states. Many actinides, such as 铀 (Uranium) and 钚 (Plutonium), are significant in the field of nuclear chemistry and energy production.