heavy metal
loosely defined subset of elements that exhibit metallic properties
AI overview
Heavy metals are elements that have metallic properties and are generally denser than other metals, though there is no strict scientific definition of which metals qualify as "heavy." They matter because many of them are toxic to humans and the environment, making them important to monitor and regulate in industrial, agricultural, and consumer products.
AI-generated from the Wikipedia summary — may contain errors.
Article
Crystals of osmium, a heavy metal nearly twice as dense as lead
Heavy metals is a controversial and ambiguous term for metallic elements with relatively high densities, atomic weights, or atomic numbers. The criteria used, and whether metalloids are included, vary depending on the author and context, and arguably, the term "heavy metal" should be avoided. A heavy metal may be defined on the basis of density, atomic number, or chemical behaviour. More specific definitions have been published, none of which has been widely accepted. The definitions surveyed in this article encompass up to 96 of the 118 known chemical elements; only mercury, lead, and bismuth meet all of them. Despite this lack of agreement, the term (plural or singular) is widely used in science. A density of more than 5 g/cm is sometimes quoted as a commonly used criterion and is used in the body of this article.