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**ryos****Member**- Registered: 2005-08-04
- Posts: 394

So, I'm sitting (lying, actually) peacefully, studying H NMR spectroscopy for my Organic Chemistry class, when I come to the topic of splitting. Basically, NMR spectrometers apply a magnetic field to the substance under study, and different hydrogens emit peaks of RF radiations at slightly different frequencies based on the structure of the molecule; this lets us infer a lot of information about the a molecule's structure.

Anyway, hydrogens that are vicinal to each other split the peaks of their neighbors. The "mini-peaks" are not the same height as each other, but rather are governed by a ratio of heights. Here are the height ratios listed in a table of my book for multiplets from a doublet to a septet:

```
1:1
1:2:1
1:3:3:1
1:4:6:4:1
1:5:10:10:5:1
1:6:15:20:15:6:1
```

Does that look familiar to anyone else? Score one for Pascal!

El que pega primero pega dos veces.

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**krassi_holmz****Real Member**- Registered: 2005-12-02
- Posts: 1,908

Wanna know something other?

Pascal's Δ

*Last edited by krassi_holmz (2006-03-01 05:17:49)*

IPBLE: Increasing Performance By Lowering Expectations.

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**MathsIsFun****Administrator**- Registered: 2005-01-21
- Posts: 7,552

Or my version: Pascal's Triangle

"The physicists defer only to mathematicians, and the mathematicians defer only to God ..." - Leon M. Lederman

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**John E. Franklin****Member**- Registered: 2005-08-29
- Posts: 3,579

On the web page krassi h. pointed out, their is a mistake in the diagram of pascal's triangle. The 186 in the bottom row should be a 286 I think.

**igloo** **myrtilles** **fourmis**

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**John E. Franklin****Member**- Registered: 2005-08-29
- Posts: 3,579

I really enjoyed MIF's pages on Pascal's triangle! My favorite part was the picture of the marbles in a tetrahedron. Wonderful implications, how the diagonal rows are possibly for each successive dimension that we cannot visualize in our 3-D world, at least that's what we can see with our eyes.

Diagonal rows:

1. all ones (0-D ?)

2. 1-D (counting numbers along a line)

3. 2-D triangle (like bowling pins)

4. 3-D triangle (like the marbles MIF has depicted)

5. 4-D triangle I am guessing, how could we prove this?????

**igloo** **myrtilles** **fourmis**

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**John E. Franklin****Member**- Registered: 2005-08-29
- Posts: 3,579

What is vicinal hydrogens?? Is it in close proximity to each other??

**igloo** **myrtilles** **fourmis**

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**John E. Franklin****Member**- Registered: 2005-08-29
- Posts: 3,579

I found this, but wish it explained more.

http://www.wfu.edu/~ylwong/chem/nmr/h1/splitting.html

**igloo** **myrtilles** **fourmis**

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**John E. Franklin****Member**- Registered: 2005-08-29
- Posts: 3,579

And this is fun to read... http://www.shu.ac.uk/schools/sci/chem/t … c/nmr1.htm

**igloo** **myrtilles** **fourmis**

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**ryos****Member**- Registered: 2005-08-04
- Posts: 394

"Vicinal" hydrogens are separated by three bonds. So, in this structure: H3--C--C--H3 (ethane), 3 hydrogens are vicinal to three others.

So yes, they're close together, but not so much in space as in bonds (though it usually means in space, too).

El que pega primero pega dos veces.

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**John E. Franklin****Member**- Registered: 2005-08-29
- Posts: 3,579

Thanks for the info, ryos, and Boy, this chemistry reading is really fascinating.

And difficult.

**igloo** **myrtilles** **fourmis**

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**krassi_holmz****Real Member**- Registered: 2005-12-02
- Posts: 1,908

Ya, It's difficult-not so easy as math!!!

IPBLE: Increasing Performance By Lowering Expectations.

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