Arsenic in the context of "Bronze"

The Bronze Age is an archaeological and anthropological term defining a phase in the development of material culture among ancient societies in Asia, the Near East and Europe. An ancient civilisation is deemed to be part of the Bronze Age if it either produced bronze by smelting its own copper and alloying it with tin, arsenic, or other metals, or traded other items for bronze from producing areas elsewhere. The Bronze Age is the middle principal period of the three-age system, following the Stone Age and preceding the Iron Age. Conceived as a global era, the Bronze Age follows the Neolithic ("New Stone") period, with a transition period between the two known as the Chalcolithic ("copper-Stone") Age. These technical developments took place at different times in different places, and therefore each region's history is framed by a different chronological system.

Bronze Age cultures were the first to develop writing. According to archaeological evidence, cultures in Mesopotamia, which used cuneiform script, and Egypt, which used hieroglyphs, developed the earliest practical writing systems. In the archaeology of the Americas, a five-period system is conventionally used instead, which does not include a Bronze Age, though some cultures there did smelt copper and bronze. No evidence of metalworking has been found on the Australian continent prior to the establishment of European settlements in 1788.

Orpiment, also known as yellow arsenic blende, is a deep-colored, orange-yellow arsenic sulfide mineral with formula As
₂S
₃. It is found in volcanic fumaroles, low-temperature hydrothermal veins, and hot springs and may be formed through sublimation.

Orpiment takes its name from the Latin auripigmentum (aurum, "gold" + pigmentum, "pigment"), due to its deep-yellow color. Orpiment once was widely used in artworks, medicine, and other applications. Because of its toxicity and instability, its usage has declined.

Cobalt is a chemical element; it has symbol Co and atomic number 27. As with nickel, cobalt is found in the Earth's crust only in a chemically combined form, save for small deposits found in alloys of natural meteoric iron. The free element, produced by reductive smelting, is a hard, lustrous, somewhat brittle, gray metal.

Cobalt-based blue pigments (cobalt blue) have been used since antiquity for jewelry and paints, and to impart a distinctive blue tint to glass. The color was long thought to be due to the metal bismuth. Miners had long used the name kobold ore (German for goblin ore) for some of the blue pigment-producing minerals. They were so named because they were poor in known metals and gave off poisonous arsenic-containing fumes when smelted. In 1735, such ores were found to be reducible to a new metal (the first discovered since ancient times), which was ultimately named for the kobold.

In chemistry, homonuclear molecules, or elemental molecules, or homonuclear species, are molecules composed of only one element. Homonuclear molecules may consist of various numbers of atoms. The size of the molecule an element can form depends on the element's properties, and some elements form molecules of more than one size. The most familiar homonuclear molecules are diatomic molecules, which consist of two atoms, although not all diatomic molecules are homonuclear. Homonuclear diatomic molecules include hydrogen (H₂), oxygen (O₂), nitrogen (N₂) and all of the halogens. Ozone (O₃) is a common triatomic homonuclear molecule. Homonuclear tetratomic molecules include arsenic (As₄) and phosphorus (P₄).

Allotropes are different chemical forms of the same element (not containing any other element). In that sense, allotropes are all homonuclear. Many elements have multiple allotropic forms. In addition to the most common form of gaseous oxygen, O₂, and ozone, there are other allotropes of oxygen. Sulfur forms several allotropes containing different numbers of sulfur atoms, including diatomic, triatomic, hexatomic and octatomic (S₂, S₃, S₆, S₈) forms, though the first three are rare. The element carbon is known to have a number of homonuclear molecules, including diamond and graphite.

Bioleaching is the extraction or liberation of metals from their ores through the use of living organisms. Bioleaching is one of several applications within biohydrometallurgy and several methods are used to treat ores or concentrates containing copper, zinc, lead, arsenic, antimony, nickel, molybdenum, gold, silver, and cobalt.

Bioleaching falls into two broad categories. The first, is the use of microorganisms to oxidize refractory minerals to release valuable metals such and gold and silver. Most commonly the minerals that are the target of oxidization are pyrite and arsenopyrite.