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
Sterling v. Velsicol Chemical Corp. Furthermore, the trenches were neither lined nor covered with any impermeable material to prevent the chemical waste from leaking into the soil. Velsicol eventually placed a clay cap over the landfill site in 1980 only after state authorities threatened a lawsuit over the imminent danger the landfill posed to the environment. Sterling v. Velsicol Chemical Corp. Sterling v. Velsicol Chemical Corp., 855 F.2d 1188 (6th Cir. 1988), was an environmental lawsuit filed by citizens of Hardeman County, Tennessee, led by Steven Sterling, who sued Velsicol Chemical Corporation for contaminating their water supply through improper disposal of toxic chemicals. In August