But silicon has several drawbacks as a carbon alternative. Because silicon atoms are much bigger, having a larger mass and atomic radius, they have difficulty forming double or triple covalent bonds, which are important for a biochemical system. Silanes, which are chemical compounds of hydrogen and silicon that are analogous to the alkane hydrocarbons, are highly reactive with water, and long-chain silanes spontaneously decompose. Molecules incorporating polymers of alternating silicon and oxygen atoms instead of direct bonds between silicon, known collectively as silicones, are much more stable. It has been suggested that silicone-based chemicals would be more stable than equivalent hydrocarbons in a sulfuric-acid-rich environment, as is found in some extraterrestrial locations. Complex long-chain silicone molecules are still less stable than their carbon counterparts.
Sploorfix: Well, we did save an entire species from gruesome slaughter.
Vexxarr: Rocks eating other rocks?! That's not slaughter, that's erosion!
Vexxarr: Rocks eating other rocks?! That's not slaughter, that's erosion!
— Vexxarr
In any event, we've worked through most of the basic communication barriers with the alien refugees. They call themselves the Spire. They aren't very talkative, but they are grateful.
They are also rocks.
Er, that's perhaps not very diplomatic. To put it another way: their bodies are crystalline formations. Exact composition unknown, for reasons you can deduce.
— Dr. Michael Davidson's journal, AI War: Fleet Command
