Chemical Forums
Chemistry Forums for Students => Inorganic Chemistry Forum => Topic started by: lemonoman on October 21, 2005, 03:28:57 PM
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Okay, amateur question.
But for a lab report I'm writing, I need to know the bond length between silicon (Si) and oxygen (O). And I absolutely can not find it, on the internet, it textbooks, anything. Plenty (in fact almost ALL) include the bond length if it was a single bond...but none discuss the double bond length.
If anyone knows a textbook, journal, internet article, etc where I might find this value, it would be greatly appreciated!
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A quick MM2 calculation puts it at 1.512 A that should be good enough for most purposes.
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See in International Tables for Crystallography in your library.
Si-O vary within 1.53 A (for trydimite) to 1.81 (for stishovite).
Hence all shorter than 1.53 A can be Si=O
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What are you making that might have an Si=O?
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I have already handed in my lab report for that class, but I will of course continue to answer/ask pertinent questions.
What I was doing was comparing the relative strengths of Si=O bonds against C=O bonds, with respect to an approximated overlap integral. We used a formula to find S(r) where r is the bond length in Angstroms, and S is the value of the overlap (from 0 to 1).
The question was asked because we had just finished synthesizing a silicone polymer, from dichlorodimethylsilane. I realize that this is a silane, not a ketone (or silicone, but the question asked referred specifically to a double-bonded oxygen.
So, in a nutshell, it was for comparison to Carbon.
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If my memory serves me, there is no precedent for a silicon-oxygen double bond in typical molecules that are stable at room temperature. I believe the word silicone is a misnomer based upon elemental composition studies that gave a composition of SiO(CH3)2 or something analogous to acetone (and hence the erroneous name).
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I would look for anything done by Robert West.