Blood - A question of SF

[den]

What would be a reasonable alternative to iron in blood? Would cobalt or manganese work? What colour would the blood be?

Comments

[ursulav.livejournal.com]

No chemist am I, but I recall reading somewhere that some of the hypothetical aliens based on other metals (such as in the Star Trek universe, where you've got everybody and their brother based on cobalt or copper or whatever) would have a terrible time in an oxygen atmosphere, as their attempts to breathe would result in their lungs corroding, or in extreme cases, catching fire. I'm not sure if that would apply here (I think they might have been talking about the silicon based giant-cheese-pizza burrowing rock monster from the original Trek. (Fine! It was called the Horta. I'm a horrible, horrible geek, okay? *sob*)) but it's worth contemplating, just in case you wind up with something with blood more reactive to oxygen than is really safe.