Silikaattirakenneyksiköiden

Silikaattirakenneyksiköiden refers to the fundamental building blocks of silicate minerals. These units are based on the silicon-oxygen tetrahedron, a structure where a central silicon atom is covalently bonded to four oxygen atoms. This tetrahedron has a net negative charge of -4 due to the difference in electronegativity between silicon and oxygen.

The way these tetrahedra link together through shared oxygen atoms dictates the vast diversity of silicate mineral structures. Isolated tetrahedra, where each tetrahedron is surrounded by cations, form the nesosilicate group. In sorosilicates, two tetrahedra share one oxygen atom, forming a double tetrahedron. Cyclosilicates feature rings of interconnected tetrahedra, while inosilicates form chains. Single chains (pyroxenes) and double chains (amphiboles) are common examples. Phyllosilicates have a sheet-like structure formed by the sharing of three oxygen atoms per tetrahedron, leading to layered silicates like micas. Finally, tectosilicates, such as quartz and feldspars, exhibit a three-dimensional framework structure where each tetrahedron shares all four oxygen atoms with neighboring tetrahedra. The specific arrangement and the types of cations that balance the negative charge within these structures determine the properties of each silicate mineral.