pyroxeenirakenteita
Pyroxeenirakenteita refers to the crystal structures of pyroxene minerals. Pyroxenes are a group of silicate minerals that form a solid solution series, meaning their chemical composition can vary continuously between two end-members. The fundamental building block of pyroxene structures is the silicon-oxygen tetrahedron, where a silicon atom is bonded to four oxygen atoms. These tetrahedra link together by sharing oxygen atoms to form infinite single chains. These single chains are then linked together by interstitial cations, typically magnesium, iron, calcium, and sodium, which occupy octahedral sites between the silicate chains. The arrangement of these chains and the types of cations present determine the specific pyroxene mineral and its properties. Common pyroxene structures include the clinopyroxenes and orthopyroxenes, which differ in the symmetry of their crystal lattice due to the way the silicate chains are aligned and the cation coordination. The presence and order of different cations within the structure are crucial for understanding the physical and chemical characteristics of pyroxenes, including their hardness, cleavage, and optical properties. These structural features are fundamental to their formation in igneous and metamorphic rocks.