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
Argentium sterling silver temperature of 802°C (1475°F) and a liquidus flow point of 899°C (1650°F). Argentium 935 silver has a solidus of 803°C (1477°F) and a liquidus of 903°C (1657°F), while Argentium 960 has a solidus of 905°C (1661°F) and a liquidus of 925°C (1697°F). Argentium sterling silver Argentium silver 935 is a modern sterling silver alloy, containing 93.5% silver. The traditional sterling alloy (92.5% silver + 7.5% copper) is modified by removing some of the copper and adding the metalloid germanium. Argentium silver 960 is a higher-purity jewellery alloy also containing germanium. It meets the standard for Britannia silver (95.84% silver) hallmarking.