Orthosilicate ion

Different minerals contain different metal cations to balance the -4 charge on the orthosilicate ion. Examples Include calcium silicate (Ca2 Si04), an important ingredient in cement, and zircon (ZrSi04), which is often sold as artificial diamond. One of the most prevalent minerals in the Earth s mantle is olivine, Af2(Si04), in which M is one or two of the abundant metal cations, Fe -, Mg -, and Mn +. 

Lewis structure and ball-and-stick model of the orthosilicate ion... 

The tetrahedral Si()44 ion is known as the orthosilicate ion. It can be regarded as the fundamental unit in the structures of most complex silicates. Several minerals including phenacite, Be2Si04, and willemite, Zn2Si04, contain this ion. Both of these minerals have tetrahedral coordination of Si044- units around the metal ion ... 

Some silicates contain small anions containing one to six Si atoms. The simplest silicate anion is the orthosilicate ion, SiCL4. In the orthosilicates forsterite, Mg2[SiC>4], and olivine, (Mg, Fe)2[SiC>4], stacking of the... 

Fig. 16.1 Various silicate structures (a) Si04 tetrahedron. When carrying a -4 charge, this is the orthosilicate ion. (b) The disilicate anion, (c) Portion of an infinite single chain. (SiOdw""- (d) Portion of an infinite double chain or band. (Si40u] . (e) Portion of a sheet or layer structure, [SiiOsl, " .

Because Si04 tetrahedra can share any number of vertices from none, in the orthosilicate ion (Si04) to four, in Si02, the extensive oxygen chemistry of silicon provides examples of all types of tetrahedral structures. Their variety is... 

Silicate Glasses. Synthetic silicates and silica are composed of oligomers of the orthosilicate ion, SiO4" Orthosilicate monomers have a... 

In isolation such a tetrahedron has a strong electron affinity. Since the bond to the silicon atom employs only one of the bonding electrons of an oxygen atom, there is room in each for one more electron in an atomic orbital of principal quantum number 2. Hence an isolated Si04 group readily forms the negative orthosilicate ion, Si04 (Fig. 9.8). 

On the other hand, we may now write formulae in which an atom of oxygen is tied by only one pair of electrons to another atom and yet have every element in the compound completely saturated. To illustrate this important point we may write the formula of perchlorate, sulfate, orthophosphate and orthosilicate ions, in which each atom has a complete shell of eight electrons. Thus [formula a in Fig. 11, substituted by this author]... 

Silicon dioxide and other compounds that contain silicon and oxygen comprise over 90% of Earth s crust. Silicates are compounds in which a silicon atom is surrounded in a tetrahedral fashion by four oxygens, as shown in Figure 22.51 . In silicates, silicon is found in its most common oxidation state, +A. The simple Si04 ion, which is known as the orthosilicate ion, is found in very few silicate minerals. We can view the silicate tetrahedra, however, as "building blocks" that are used to build mineral structures. The individual tetrahedra are linked together by a common oxygen atom that serves as a vertex of both tetrahedra. 

The basic Si04 orthosilicate ion can combine with two ions to form Mg2Si04... 

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