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Topic: Why is each methyl written differently in lewis structures?  (Read 1192 times)

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Offline levaa

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Why is each methyl written differently in lewis structures?
« on: April 21, 2019, 06:12:47 AM »
I'm attempting to self-teach organic chemistry, and have encountered an issue.

When writing (CH3)3C (three methyls linked to one carbon), it is apparent each methyl is written differently. Rather than just three linked CH3s, there is a CH3, CH2, and H3C.

Why is this?

Offline levaa

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Re: Why is each methyl written differently in lewis structures?
« Reply #1 on: April 21, 2019, 07:37:20 AM »
Lmao.

I misread the answer. It is a carbon linked to two CH3s and an H3C. I did not realize H3C was also methane.

Offline spirochete

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Re: Why is each methyl written differently in lewis structures?
« Reply #2 on: April 22, 2019, 12:10:10 AM »
One note on terminology: "CH3" is a methyl group, and not methane. Carbon makes 4 bonds, so CH3 is not a stand alone molecule, but rather a substituent/group that must be bonded to another carbon. Methyl is an alkyl group, and such groups end in "-yl". Alkanes are stable molecules where all the carbons make four bonds, and their names and in -ane. For example CH4 is methane.

Also, "methyl" doesn't really mean just one carbon. It literally means CH3. CH2 and CH have other names, but its probably best not to get too bogged down in terminology and focus on the concepts also.

(CH3)3C is also not a complete molecule, because the central carbon is only making three bonds. It is called a "tert-butyl" group. This article about isomers and terminology might be helpful: https://www.masterorganicchemistry.com/2011/11/10/dont-be-futyl-learn-the-butyls/

Offline AWK

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Re: Why is each methyl written differently in lewis structures?
« Reply #3 on: April 22, 2019, 02:24:58 AM »
Such a record is not yet Lewis structure. This is the semi-structural chemical formula.

H3C-CH2-CH3 and
CH3-CH2-CH3 are exactly the same formulas
AWK

Offline OrganicDan96

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Re: Why is each methyl written differently in lewis structures?
« Reply #4 on: April 22, 2019, 05:56:42 AM »
people often write H3C to make it clear that the bond is to the carbon atom eg H3C-CH3

Offline Babcock_Hall

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Re: Why is each methyl written differently in lewis structures?
« Reply #5 on: April 25, 2019, 09:54:13 AM »
@OP, What you originally wrote is simply a tertiary butyl (tert-butyl) group.

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