Talk:Fischer projection

Reference to obscure computational chemistry paper removed. It has nothing to do with the Fischer projection, nor is it an accessible piece of writting suitable for an encyclopedia entry.

129.215.221.247 (talk) 13:09, 26 March 2009 (UTC)

Confusion
Someone please address this in the article.

In a fischer projection, how can ALL the vertical bonds be facing away from the viewer if 2+ C's are bonded with a vertical line? If you're looking at the top C, then the bottom C is behind it. But if you're looking at the bottom C, then the top C is behind it, which is paradoxical.

128.143.65.169 (talk) 17:58, 28 June 2009 (UTC)


 * The problem is the word facing away they are not behind they are only looking away from you. The image Visualizing a Fischer projectionwith the ABCD can make this a little bit clearer. The person is looking directly between C and D and these two bonds go left and right but if the person also opens the second eye he will notice that the two bonds also come towards him. This is indecated by the bold lines in the buble. The other two bonds to A nad B are going away from him. This is called in the description  facing away.--Stone (talk) 19:50, 28 June 2009 (UTC)


 * No, that doesn't help. A diagram of a molecule with more than one carbon, and how its Fischer projection corresponds to other ways of visualizing its structure, would help. I'm pretty sure the description is just wrong, since there's no way that a rule vaguely like that could give you six carbons in a vertical line. 17:11, 19 December 2010 (UTC) —Preceding unsigned comment added by 186.22.58.35 (talk)


 * I agree -- the illustration of the single carbon is not very instructive. I'll try to generate a figure that better explains the Fischer projection.  Jon Chui (talk) 06:01, 27 December 2010 (UTC)

Rules for rotating
Should provide more explicit details on proper rotating/rearranging projections. I.e. if you hold one substituent steady, you can rotate all the other ones clockwise or counterclockwise (skipping the spot held in place) without affecting chirality at that location. Also you can flip 180 degrees (I think).CrocodilesAreForWimps (talk) 01:31, 16 August 2012 (UTC)

Inconsistency between article and illustration?
In the "conventions" section, it says that all bonds are represented by horizontal or vertical lines. This seems to imply that the illustration of the D-glucose chain is incorrect, since it contains two bonds drawn as diagonal lines, and since the bottom CH2OH group has none of its bonds illustrated. -- Creidieki 06:06, 25 December 2012 (UTC)


 * Nothing bad with it. Bad is the presence of C-atom labels in the middle of the stereogenic crosses. It means that it's just a structural representation but not a Fischer projection. — Mfomich (talk) 17:29, 9 February 2013 (UTC)

Away from the viewer?
In the article I read: "In a Fischer projection, all horizontal bonds project toward the viewer, while vertical bonds project away from the viewer."

This does not make sense to me. Do C-C links in the middle of a chain point toward me or away from me? It depends on which C is the center of the world... Does the sentence only refer to links in the end of the chain? Are not some of them free to rotate freely? Thanks. — Preceding unsigned comment added by Kiskrof (talk • contribs) 09:35, 3 August 2017 (UTC)


 * I couldn't make head or tail of that part of the article either. Polar Apposite (talk) 15:31, 9 December 2022 (UTC)

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Fischer projections don't show C atoms
The representation of glucose which is supposed to be a Fischer projection shows every carbon in the chain. I thought that Fischer projections represent carbon atoms - especially chiral carbons - just as the point of intersection of a vertical line and a horizontal line, without writing C for each carbon (unless the carbon is at the end of a chain or is on a substituent group off the main chain). — Preceding unsigned comment added by 98.207.66.179 (talk) 07:05, 21 August 2018 (UTC)

Wiki Education assignment: Honors Organic Chemistry I
— Assignment last updated by Holley62 (talk) 21:30, 15 November 2022 (UTC)

The Natta projection is missing two hydrogens.
The Natta projection is missing two hydrogens, or perhaps shouldn't be showing any hydrogens. To show all but two hydrogens is wrong isn't it? Polar Apposite (talk) 15:40, 9 December 2022 (UTC)

That’s because it’s a skeletal formula and there is no stereochemistry to indicate. It’s appropriate in this context. Ben (talk) 18:47, 9 December 2022 (UTC)


 * There's also no stereochemistry to indicate with the hydrogen on the C-1 atom, surely? Polar Apposite (talk) 20:20, 11 December 2022 (UTC)