text: Silicon can form sigma bonds to other silicon atoms (and disilane is the parent of this class of compounds). However, it is difficult to prepare and isolate SiH (analogous to the saturated alkane hydrocarbons) with n greater than about 8, as their thermal stability decreases with increases in the number of silicon atoms.  Silanes higher in molecular weight than disilane decompose to polymeric polysilicon hydride and hydrogen.  But with a suitable pair of organic substituents in place of hydrogen on each silicon it is possible to prepare polysilanes (sometimes, erroneously called polysilenes) that are analogues of alkanes. These long chain compounds have surprising electronic properties - high electrical conductivity, for example - arising from sigma delocalization of the electrons in the chain.
  Even silicon–silicon pi bonds are possible. However, these bonds are less stable than the carbon analogues. Disilane and longer silanes are quite reactive compared to alkanes. Disilene and disilynes are quite rare, unlike alkenes and alkynes. Examples of disilynes, long thought to be too unstable to be isolated were reported in 2004.