transactinide elements; super-heavy elements
Technical term in chemistry for elements with atomic numbers greater than 103 (beyond lawrencium).
All transactinide elements are radioactive.
Particle accelerators are used to synthesize transactinide elements.
Compound of 超 (chō, 'beyond') + アクチノイド (akuchinoido, 'actinide') + 元素 (genso, 'element').