karbonaatide

Karbonaatide is a term used in mineralogy and inorganic chemistry to refer to compounds or minerals that contain the carbonate group, CO3^2-, in combination with metal cations. In this sense, karbonaatide encompasses the broad class of carbonate minerals found in nature as well as related synthetic compounds.

Structure and composition: The carbonate ion consists of a central carbon atom bonded to three oxygen atoms in a planar arrangement. In minerals, carbonate groups link to metal cations such as calcium, magnesium, iron, and manganese, creating a variety of crystal structures. The specific cation combination, charge balance, and ionic radii influence the mineral’s crystal system, symmetry, hardness, and other properties.

Occurrence and formation: Carbonates are widespread in Earth’s crust, especially in sedimentary rocks, hydrothermal veins, and some metamorphic settings. They form by direct precipitation from aqueous solutions, by biological processes in oceans and lakes, or by metasomatic replacement during geological alteration. The most well-known carbonate minerals include calcite (CaCO3), dolomite (CaMg(CO3)2), siderite (FeCO3), and magnesite (MgCO3).

Properties and uses: Carbonate minerals are typically relatively soft and may react with dilute acids, releasing carbon dioxide. They are economically important as building materials (limestone and marble), sources of lime and cement, and feedstocks for a range of chemical processes. Their properties vary with composition and impurity content, influencing applications and handling.

Etymology and classification: The term karbonaatide reflects the carbonate basis of these compounds. In English mineralogy, the broader category is usually referred to as carbonates, with individual minerals named after their constituent cations. See also carbonate ion and carbonate mineral.