I was told that 'water' was the most common material in the universe and I disputed that claim. I was met with the argument that hydrogen and oxygen were the most common atoms in the world so water was as well. If this is true, then how come we can't find water anywhere in outer space? It must be the collection of 2 hydrogen atoms and 1 oxygen atom that is so rare then?

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    $\begingroup$ Try to read this wiki en.wikipedia.org/wiki/… $\endgroup$
    – saldenisov
    Mar 26 '14 at 10:36
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    $\begingroup$ It is true that hydrogen is the most common atom in the Universe, and oxygen is one of the most common, too (though a couple orders of magnitude rarer). If that's the case, then it should be apparent that $\ce{H2}$ should be more common than $\ce{H2O}$, since the latter has the same amount of hydrogen but requires one more atom. Indeed, according to Wikipedia, hydrogen gas is the most common molecule in interstellar space, followed by carbon monoxide (presumably because of the exceptionally strong bond in $\ce{CO}$). $\endgroup$ Mar 26 '14 at 12:18

The Big Bang started with about 3/4 hydrogen atoms and 1/4 helium atoms. Add a pinch of lithium and a whisper of boron. Supernovae since then have released a lot of helium. Heavier elements are still rare.

"The most common [molecular] material in the universe" must survive photolysis, radiolysis, and reaction. Water is poor candidate.

What is out there. CO is the marker.
Molecules in space, isotopically and by
atom count


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