Sci-fi often mentions silicon based life and I recall asking about it in a biology class ages ago. Never diving deeply, I just assumed it was a possibility somewhere. This video goes over some basics in physics and chemistry, which disadvantage non-carbon-based life, Carl Sagan's "carbon chauvinism. The main parts are:
- difference in bond angles, where silicon prefers to bond with oxygen than itself, so you don't get long complex chains like with hydrocarbons
- difference in energy to bond, which carbon does with less energy
- difference in solubility, where carbon doesn't dissolve immediately in water (the universal solvent) but silica (sand, 1 silicon and 2 oxygen) does instantly, requiring a different solvent for silicon based life
- difference in bond angles, where silicon prefers to bond with oxygen than itself, so you don't get long complex chains like with hydrocarbons
- difference in energy to bond, which carbon does with less energy
- difference in solubility, where carbon doesn't dissolve immediately in water (the universal solvent) but silica (sand, 1 silicon and 2 oxygen) does instantly, requiring a different solvent for silicon based life