siloxane

240px|right|Polydimethylsiloxane is a prevalent siloxane.|thumb

In organosilicon chemistry, a siloxane is an organic compound containing a functional group of two silicon atoms bound to an oxygen atom: . The parent siloxanes include the oligomeric and polymeric hydrides with the formulae {{chem2|H[OSiH2]_{n}OH}} and {{chem2|[OSiH2]_{n}|}}. Siloxanes also include branched compounds, the defining feature of which is that each pair of silicon centres is separated by one oxygen atom. The siloxane functional group forms the backbone of silicones {{chem2|[\sR2Si\sO\sSiR2\s]_{n}|}}, the premier example of which is polydimethylsiloxane (PDMS). The functional group (where the three Rs may be different) is called siloxy. Siloxanes are manmade and have many commercial and industrial applications because of the compounds’ hydrophobicity, low thermal conductivity, and high flexibility.