You could use some hydrogen - the most common element in the universe
Also if you want to make life you will need some elements that can form long chains (like carbon does) to make some sort of proteins (or something similar).
Now in real life the only element that we know of that can form such chains is carbon (hydrocarbons) that connects it's atoms with other with C-C bonds. If you search more you'll find that other substances forming long chains don't have direct bonds between the same elements (except maybe for sulphur, but it's chains are quite short).
So, returning to your question:
1. Zrzi species: silicon and aluminium, they can form long chains. Silicon with oxygen: -Si-O-Si-O- that is glass
and the three elements together: -Si-O-Al-O-Si-O-Al- forms a common rock
but hey, it's science-fiction
2. Dalasians: phosphorous can exist in polymeric form on it's own (like sulphur - short chains) or in polyphosphate form -P-O-P-O-P- (polyphosphates with one, two and three P atoms are very important in human body, they form AMP, ADP and ATP - source of energy, P-O bond is high-energetic one).
Of course the chains that I wrote are not linear but ramified (it it's the correct word
). Hope that it helped a bit.
PS. If I was to write some sci-fi story I wouldn't mention biochemistry of alien life and left it a mystery
Or if I had to for the sake of the story I would stick to good old carbon