silicaattetraëder

Silica tetraëder refers to the fundamental structural unit of many silicate minerals. It is a molecule composed of one silicon atom bonded to four oxygen atoms. This arrangement forms a three-dimensional tetrahedron, with the silicon atom at the center and the oxygen atoms at the vertices. The silicon atom has a charge of +4, and each oxygen atom has a charge of -2, resulting in an overall charge of -4 for the isolated tetraëder unit ([SiO4]4-).

In silicate minerals, these silica tetraëder units are not typically found in isolation. Instead, they link together in various ways by sharing oxygen atoms. This sharing can occur between one, two, three, or all four oxygen atoms of a tetraëder, leading to different structural arrangements. These arrangements include isolated tetraëder, pairs of tetraëder, rings of tetraëder, single chains, double chains, sheets, and three-dimensional frameworks. The way these tetraëder units connect significantly influences the physical and chemical properties of the resulting silicate mineral, such as its hardness, cleavage, and melting point. The silica tetraëder is the building block for the vast majority of the Earth's crust.