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Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula SiO 2, commonly found in nature as quartz. [ 5 ] [ 6 ] In many parts of the world, silica is the major constituent of sand .
A silicon–oxygen bond (Si−O bond) is a chemical bond between silicon and oxygen atoms that can be found in many inorganic and organic compounds. [1] In a silicon–oxygen bond, electrons are shared unequally between the two atoms, with oxygen taking the larger share due to its greater electronegativity.
A molecule may be nonpolar either when there is an equal sharing of electrons between the two atoms of a diatomic molecule or because of the symmetrical arrangement of polar bonds in a more complex molecule. For example, boron trifluoride (BF 3) has a trigonal planar arrangement of three polar bonds at 120°. This results in no overall dipole ...
Products often vary with the stoichiometry of the silicide reactant. For example, Ca 2 Si is polar and non-conducting and has the anti-PbCl 2 structure with single isolated silicon atoms, and reacts with water to produce calcium hydroxide, hydrated silicon dioxide, and hydrogen gas.
Oxidation of organosilicon compounds, including siloxanes, gives silicon dioxide. This conversion is illustrated by the combustion of hexamethylcyclotrisiloxane: ((CH 3) 2 SiO) 3 + 12 O 2 → 3 SiO 2 + 6 CO 2 + 9 H 2 O. Strong base degrades siloxane group, often affording siloxide salts: ((CH 3) 3 Si) 2 O + 2 NaOH → 2 (CH 3) 3 SiONa + H 2 O
In group 16 silicon dioxide is a very common compound that widely occurs as sand or quartz. SiO 2 is tetrahedral with each silicon atom surrounded by 4 oxygen atoms. Numerous crystalline forms exist with the tetrahedra linked to form a polymeric chain. Examples are tridymite and cristobalite.
A large molecule with an ionized group is technically an ion, but its behavior may be largely the result of non-ionic interactions. For example, sodium stearate (the main constituent of traditional soaps) consists entirely of ions, yet it is a soft material quite unlike a typical ionic solid. There is a continuum between ionic solids and ...
Examples of network solids include diamond with a continuous network of carbon atoms and silicon dioxide or quartz with a continuous three-dimensional network of SiO 2 units. Graphite and the mica group of silicate minerals structurally consist of continuous two-dimensional sheets covalently bonded within the layer, with other bond types ...