Period 6 element form, as an X-ray radiocontrast agent for imaging the human gastrointestinal tract. Soluble barium compounds are poisonous due to release of the soluble barium ion, and have been used as rodenticides. New uses for barium continue to be sought. It is a component of some "high temperature" YBCOsuperconductors, and electroceramics. The lanthanide or lanthanoid (IUPAC nomenclature) series comprises the fifteen metallic chemical elements with atomic numbers 57 through 71, from lanthanum through lutetium. These fifteen elements, along with the chemically similar elements scandium and yttrium, are often collectively known as the rare earth elements. The informal chemical symbol Ln is
Metallic dragon Metallic dragon Metallic dragon is a classification of dragon found in the role playing game "Dungeons & Dragons". In this setting metallic dragons are of good alignment. Bahamut is the deity of good-aligned dragons and metallic dragons, and currently the only known Platinum dragon in existence. Metallic dragons have played a large role in D&D's various monster compilation books, and for most of the game's history five main types - brass, copper, bronze, silver, and gold - were presented as roughly analogous to the five types of chromatic dragons. The fourth edition of the game's second "Monster Manual" substituted iron