December 24, 2024, 08:57:48 PM
Forum Rules: Read This Before Posting


Topic: Si=O bond length  (Read 10801 times)

0 Members and 1 Guest are viewing this topic.

Offline lemonoman

  • Atmospheric
  • Chemist
  • Full Member
  • *
  • Posts: 607
  • Mole Snacks: +71/-8
  • Gender: Male
Si=O bond length
« on: October 21, 2005, 03:28:57 PM »
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!

Offline Mitch

  • General Chemist
  • Administrator
  • Sr. Member
  • *
  • Posts: 5298
  • Mole Snacks: +376/-3
  • Gender: Male
  • "I bring you peace." -Mr. Burns
    • Chemistry Blog
Re:Si=O bond length
« Reply #1 on: October 21, 2005, 05:33:05 PM »
A quick MM2 calculation puts it at 1.512 A that should be good enough for most purposes.
Most Common Suggestions I Make on the Forums.
1. Start by writing a balanced chemical equation.
2. Don't confuse thermodynamic stability with chemical reactivity.
3. Forum Supports LaTex

Offline AWK

  • Retired Staff
  • Sr. Member
  • *
  • Posts: 7976
  • Mole Snacks: +555/-93
  • Gender: Male
Re:Si=O bond length
« Reply #2 on: October 26, 2005, 05:03:17 AM »
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
« Last Edit: October 26, 2005, 05:17:45 AM by AWK »
AWK

Offline DrCMS

  • Chemist
  • Sr. Member
  • *
  • Posts: 1306
  • Mole Snacks: +212/-84
  • Gender: Male
Re:Si=O bond length
« Reply #3 on: November 09, 2005, 02:53:17 PM »
What are you making that might have an Si=O?

Offline lemonoman

  • Atmospheric
  • Chemist
  • Full Member
  • *
  • Posts: 607
  • Mole Snacks: +71/-8
  • Gender: Male
Re:Si=O bond length
« Reply #4 on: November 09, 2005, 03:23:47 PM »
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.
« Last Edit: November 09, 2005, 03:24:11 PM by lemonoman »

Offline Dude

  • Chemist
  • Full Member
  • *
  • Posts: 237
  • Mole Snacks: +42/-9
  • I'm a mole!
Re:Si=O bond length
« Reply #5 on: November 09, 2005, 05:26:32 PM »
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).

AgG

  • Guest
Re:Si=O bond length
« Reply #6 on: November 10, 2005, 07:59:21 PM »
I would look for anything done by Robert West.  

Sponsored Links