The Periodic Table

Abcd

03:47

@Zhe I thought it was obvious, but should've mentioned it in the exception.

yesterday, by Abcd

@Zhe You said it's planar chirality, but I don't get how.

How is there restricted rotation of the topmost C.

What if the compound was methyl ethanol?

Then you'd say its not chiral.

But look here too methyl ethanol group is present at the top.

Zhe

04:08

As drawn they're not enanatiomers

It's just rotamers

If the OH were up and down and those positions were locked due to restricted rotation, they were be enatiomeric

Abcd

So they aren't optically active @Zhe?

Zhe

Not as drawn, no

The problem is that methyl is larger than OH, so they're out of plane

Abcd

But they are atropisomers?

Zhe

yes

There isomers due to restricted rotation

Abcd

@Zhe Okay, why's there restricted rotation.

This is so confusing.

Zhe

04:16

Here's the place where you actually might consider building the model

There's too much steric hindrance to allow the methyl groups to be in the plane of the naphthyl moiety

The alternative is for you to draw the Newman projection

Rick

@Abcd That C-C bond between the ring and the top C is kinda locked in place

9

A: Chirality of biphenyls

Yes, the molecule should exhibit chirality below room temperature. In the optimised1 molecular configuration the molecule cannot be superimposed on its mirror image. This is because of the out-of-plane rotation of the nitro groups. The thermodynamic most favourable structure is of $C_2$ symm...

See the gifs in this answer

Abcd

06:20

@Rick But its not a biphenyl, its a napthyl

But they should rotate.

There's no problem in rotation.

The C is free to rotate.

@Rick Why is C locked in place?

And if C is locked, it should be chiral :/ which @Zhe said no to.

Rick

13:05

Yes, it's similar..That C-C bond isn't free to rotate because when it does, the two bulky methyl groups will get sterically hindered by the rings and it's hydrogens, so the bond is locked in place to minimize this effect.

It is chiral, as the 2 mirror images are non-superimposable because of this "locked" bond

Abcd

13:35

Thanks for you answer @Martin-マーチン. Which software do you use for making those amazing GIFs?

Martin - マーチン

chemcraft and gimp

imgur has those 2mb restrictions, so you need to reduce the quality...

okidoki... have a good weekend y'all

Zhe

@Abcd Whoa, I didn't make a blanket statement...

The example you showed is not chiral because of how rotation is locked

Substituted biphenyls frequently are chiral

Abcd

@Zhe Sorry, I misunderstood.

Zhe

14:03

Stereochemistry can be confusing

There's a reason the Eliel book is a door stop

Abcd

14:19

@Zhe Any link to that?

Zhe

You to the actual text?

Abcd

yes

Zhe

That would be unethical

You can purchase a copy but it's like a couple of hundred dollars. I wouldn't recommend it

It is also, like March, not a read-cover-to-cover book

Abcd

14:37

What would be a pre-MOT explanation to the stability of gauche form of hydrazine over the anti form?

It's counter-intuitive.

There are minimum repulsions in the anti form.

Zhe

14:50

What makes you think there is a valid explanation?

Sometimes simple theories are wrong. That's why we need better theory

Gaurang Tandon

15:23

Sorry to interrupt here, but can anyone confirm from the 2013 IUPAC blue book if the preferred IUPAC name in alkyl ethers is "alkoxy" or "alkyloxy"? I've been using "alkoxy" since I was a kid, but ACD ChemSketch keeps generating "alkyloxy" instead. Thanks!

Rick

@Zhe So that molecule is achiral? If rotation is locked, shouldn't that mean that the mirror images are not superimposable?

Zhe

@Rick Which one?

Rick

15:54

12 hours ago, by Abcd

yesterday, by Abcd

@Zhe this one

Zhe

16:07

No, it depends on how the rotation is locked

Those two are drawn correctly

The OH is in the plane of the naphthyl ring

So there is a plane of symmetry

If the OH were out of plane and prevented from crossing the plane, then it would be chiral, but that is not the case

S.Chevalier

18:54

Good evening (/morning/day/whatever) all. I'm just too curious : why is paracetamol in the naughty corner ?

Zhe

¯\_(ツ)_/¯

S.Chevalier

Hum.. the plot thickens.

Loong

8

A: Why is [user] again suspended?

As we have said repeatedly, we (moderators) do not share information about specific suspensions with anyone except other moderators and the SE team.* This means that the moderators will not explain to you what happened, and nobody else on this site knows what happened. While other non-moderator u...

skullpatrol

inquiring minds want to know :P

pentavalentcarbon

19:31

probably some voting crap, that's what it usually is

Linear Christmas

21:22

@pentavalentcarbon That was actually meant as a joke (note use of italics), perhaps a poor one though; but I couldn't take the topic seriously

Also, if anyone wishes to discuss or challenge the answer to Howcome is ∆G ≤ 0 used for spontaneity in electrochemistry, not ∆G ≤ W(other)?, feel free to ping me to chat

I think it's important to get it dead-on correct (even though I share almost 100% of the responsibility as the answerer)

I also encourage everyone answering thermodynamics questions to explicity use $\Delta_\pu{r} \equiv \partial / \partial \xi$ whenever pertinent instead of the confusing and often very incorrect bare captial delta $\Delta$ (I am at fault here as well)

orthocresol

22:12

@LinearChristmas, is there a reason why you are using \operatorname{d}?

Also, thanks for the edit the other day. You are now welcome to edit all my other answers with \mathrm{d}q and \mathrm{d}w...

Linear Christmas

@orthocresol I have used both \operatorname{d} and \mathrm{d} in the past; I think \operatorname should be more correct as per this answer

but I realise this is not self-consistent since the same scrutiny should be applied to the Greek deltas

@orthocresol no problem, I might if I come upon such answers

when answering thermodynamics questions, doing a literature search on SE leads inevitably to some of your work here from '15 or '16

Zhe

@orthocresol Did you end up reading my thesis?

orthocresol

@Zhe Yes, but only briefly

Linear Christmas

22:29

@orthocresol What is the difference between ∆G and ∆G°? also: you probably already knew this but to be pedantic $p^\circ = \pu{1 bar}$ is not part of the definition of a standard state, just some well-defined value not necessarily $\pu{1 bar}$ (not up for editing at the moment though)

orthocresol

That's truly pedantic.

I'm impressed

Linear Christmas

yes, painfully-pedantic

that's my personality if I haven't been drinking

orthocresol

I'm not particularly happy with that answer in general. I think it is worded too obtusely.

Linear Christmas

looks up meaning of obtuse

orthocresol

More than 90° and less than 180°.

Linear Christmas

22:35

haha

I wouldn't actually criticise the answer too strongly

I find the approach well takes into account the original aim and level of confusion in the question

disclaimer: the compliment does not account for the positive bias toword mister moderator

orthocresol

You're too kind. Anyway, I will edit the wording to reflect your comment above, which I actually did not know about until you alerted me to it.

(I've found the relevant passage in the Green Book)

Linear Christmas

as a good samaritan, I recommend this cutie for discussions of standard quantities: old.iupac.org/publications/pac/1994/pdf/6603x0533.pdf

it also discusses pressure dependancies which are often omitted

M.A.R.

Linear Pedantic

@Loong ANSWER ME. WHY IS USER AGAIN SUSPENDED

Linear Christmas

22:53

good to see MAR hasn't changed

last time you were bending linear christmas

(along with Jan)

M.A.R.

@LinearChristmas I have changed. My underwear would have stunk like a skunk if I hadn't

Linear Christmas

do skunks really smell?

before spraying, obviously

they are kept as pets in some cases (after neutralising), so I doubt it

<- pedantic?

M.A.R.

No, you're not pedantic at all.

AT ALL.

Slowly pulling out a gun

Linear Christmas

cut off one head, mate

cut off one head...

M.A.R.

Making Linear Christmas a Ring Christmas

@LinearChristmas well, humans spray more often

Linear Christmas

23:05

@M.A.R. I laughed, well done

M.A.R.

My work here is done

for the second

Linear Christmas

@M.A.R. could you perhaps expand a bit? as it stands, it's a bit unclear what you mean by this

M.A.R.

@LinearChristmas pls don't answerz noob if you obviously do not knows the answer and have obviously no knowledge of chemistry or anythings else. If you downvote this may the wrath of Zeus be upon you. May your loved ones die in pain. If you vote to close this, @#$#$##$%€¥£##$$@@ BEEP BEEP "Sorry, we're facing technical difficulties at the moment"

Linear Christmas

@M.A.R. i dont want to know about chemistry what is the answer to this pplzz i have test 10 min ago

M.A.R.

HURRY UP TEACHER TAKE TEST PAPER

Linear Christmas

23:12

why u be so rude if you dont help shut up and go away

M.A.R.

THIS SITE NO HELPFUL TO FIELD EXPERTS

I AM VARY POWERFUL MILLI TERRY COMMANDER AND I ORDER NOT 2 USES THIS SITE ANYONE

Linear Christmas

writes an answer with 10^4 characters in microsoft word then purposely removes line spaces when answering on SE

will not respond to any comments

M.A.R.

For future reference, MILLI TERRY refers to one thousandth of TERRY

Linear Christmas

why you not understand reference not necessary this is basic FACT

M.A.R.

@LinearChristmas flagging for mod attention "Hi. May God bless you. This answer seems to contain an error in char 5647. Kthx. I love chemistry. Marcus from Siberia"

Linear Christmas

23:17

@M.A.R. is MILLI TERRI the first part in M.A.R.

M.A.R.

@LinearChristmas pfft, im not spending time with losers who know no chem and use upper case

@LinearChristmas yes, its full form is MILLI TERRY AWESOME RACCOON

Linear Christmas

but you will communicate with losers who know no chem OR use upper case?

(just to clarify)

@M.A.R. thats just beautiful, I have nothing to add

M.A.R.

This site has lost its use, and downgraded from real chemistry to pedantry.

I am too awesome to participate.

I will go to Quora instead, where Stephen Hawking hangs.

And Bertrand Russell used to drank tea with Mendeleev

Quora is so awesome, the account creation requirements are three PhDs in unrelated fields

Bye bye, SE. You will miss me as your greatest contributor.

anxiously checking meta SE to see how many people cry for his leave

Linear Christmas

quora, really?

isn't that, like, peer-reviewed and all?

i have seen many people comment on single question, so...

M.A.R.

Only peer reviewed when you hate SE

Linear Christmas

23:25

fair enough

I think some other forums are even better suited though

post-quitting

foreign-language forums are a good start

M.A.R.

IT IS ONLY FAIR IF YOU ANSWER MY EXPERT QUESTION

Linear Christmas

where u only understand chemical reactions written out

sir if u are and expert kindly answer this question

2

M.A.R.

DOES NACL TAISTE LIKE SUGER?

@LinearChristmas according to me, benzene will does an SN3 on carbonyl oxygen

If you disagree, you are dumb

NOW ANSWER MY QUESTION PLS

NOW

Okie dokie, I gotta sleep. But this conversation deserves a bookmark

Pacing ourselves in users ' position selflessly

46 mins ago, 42 minutes total – 63 messages, 2 users, 0 stars

Bookmarked 20 secs ago by M.A.R.

2

orthocresol

@LinearChristmas This was too real.

Linear Christmas

@M.A.R. no answer this before you sleep kind sir

looks up and pings you under every post you have written

pentavalentcarbon

23:38

@LinearChristmas well this sure is old

Linear Christmas

@orthocresol who said we need to make stuff up to be scary/funny, reality is good enough

@pentavalentcarbon hah, there was a search box at the top right, which prompted the response

pentavalentcarbon

@orthocresol I thought we forgot about that...best to let some things die quietly

M.A.R.

@orthocresol no kidding

Pacing ourselves in users ' position selflessly

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