Pyrosilicate:
In pyrosilicate, two oxygen atoms of [SiO4]4- are shared. This results in the formation of a dimer structure with two silicon atoms and four oxygen atoms. The two oxygen atoms are shared between the two silicon atoms, creating a bridge between them.

Sheet silicate:
In sheet silicate, the [SiO4]4- tetrahedra are arranged in a sheet-like structure. Each tetrahedron is connected to three other tetrahedra through shared oxygen atoms, forming a two-dimensional sheet. The oxygen atoms are not shared between tetrahedra in this case.

Linear chain silicate:
In linear chain silicate, the [SiO4]4- tetrahedra are arranged in a linear chain. Each tetrahedron shares two oxygen atoms with adjacent tetrahedra, forming a continuous chain. The oxygen atoms are shared in a linear fashion, creating a one-dimensional structure.

Three-dimensional silicate:
In three-dimensional silicate, the [SiO4]4- tetrahedra are connected to each other in a three-dimensional network. Each tetrahedron shares all four of its oxygen atoms with other tetrahedra, resulting in a highly interconnected structure. This three-dimensional network gives rise to various types of silicate minerals, such as quartz and feldspar.

Overall, the structure of silicate can vary depending on the arrangement and sharing of oxygen atoms between the [SiO4]4- tetrahedra. The different structures have different physical and chemical properties, and they play a crucial role in the formation and characteristics of various silicate minerals.