In things about alternatives to carbon-based life, most of the time you see stuff about silicon-based analogues of organic molecules. But silanes are much less stable than the corresponding alkanes. But I just had a thought: What about polyphosphates? The standard 'phosphate' anion is PO₄³⁻ but there is also pyrophosphate which is two phosphates sharing an oxygen, P₂O₇⁴⁻, and this pattern can continue into long polymeric polyphosphates, which are generally stable.