The Periodic Table - 2017-03-21

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12:21 AM

@Buttonwood @DSVA Hey guys, I like to thank you for suggesting pymol. I finally managed to align and compare the two molecules. Just as I expected, the slight deviation of the structures from the double and triple zeta calculations are not covered by the 4 molecular parameters of interest in my project. This might be important in assessing which part of the metal complex is sensitive to what basis set and calculation methods when we get to the unknown samples (which were not synthesized yet)

@Buttonwood Alas no longer :(

pentavalentcarbon

1:15 AM

@Buttonwood How could I forget the number one problem. It is so easy to get a borked Word document even doing simple stuff. Save a document with Word 2011 for Mac, stuff is messed up when you open it in latest Word for Windows, someone else accidentally duplicated a bunch of text in the same document with Word 2016 for Mac...collaborating with it is impossible. Version control...basically non-existent.

3 hours later…

4:13 AM

@Loong Is Og technically a noble gas? If so, the noble-gases tag description needs a further tweak.

Also, shouldn't the atomic numbers be subscripts, not superscripts? I can go back in there and fix them, if so.

4:26 AM

Also, to no one in particular, we really need to lure airhuff into chat.

7 hours later…

10:56 AM

-1

Q: Hello everyone!I want some suggest from you!.

There's a butterfly in a glass bottle and you'll pump some gas into the bottle and the close the bottle?So,what will happen to that butterfly in thus bottle?.

physical-chemistry

Poor butterfly...

11:08 AM

Oct 14 '16 at 12:24, by Loong

That reminds me how some students I was supervising tried to anaesthetize a fly with chloroform.

11:57 AM

Seriously,why down votes. Isn't it related to chemistry?

@Loong or @orthocresol ^

2 hours later…

2:11 PM

This guy:

161 6

molecular-orbital-theory organic-chemistry quantum-chemistry redox synthesis ab-initio acid-base

This answer:

-3

A: Why can two carbon atoms not form more than triple bond with each other?

The poor 10th-grader. People, just because you know some stuff doesn't mean you have to show it. There is no reason why carbon shouldn't be able to form a quadruple bond. In a way it should be able to form a sixtuple bond with its core electrons. The reason why it doesn't do that is because the ...

This comment:

@hBy2Py : I'm not sure you really know what you are talking about. The term "likelihood" in this context alone is "badly flawed". There are several other problems and misunderstandings in your answer, but I don't think this is the time and place. I also gave an answer for a 10thgrader. I see you are on some kind of purity trip to keep this forum clean from non-publishable answers, but please keep in mind that most questions here get asked by kids. — AMT 17 mins ago

{{{>.<}}}

(゜o゜)

I’ld love to say Nuke from orbit but I think it should stay as a bad example? I mean it tries to answer the question it just fails so miserably at it …

@Jan I don't believe this. I will delete this question shortly because apparently it's not according to conventional chemistry, but you sir need to learn some stuff about quantum mechanics. Of course the core electrons contribute. — AMT 57 secs ago

LOL!

user image

@Jan I have to save this for posteriortiy because it will get deleted. So screenshotted!

2:37 PM

I'm not sure about that answer. It's just a lot of waffling without any substance.

At least the opening lines "The poor 10th-grader. People, just because you know some stuff doesn't mean you have to show it" got taken out. So that's a win, from my point of view...

3

A: Butterfly in a sealed glass bottle

It will use the air for respiration and eventually die afterwards.

...

@Jan @ortho I can't tell whether the guy is serious, or trolling.

I mean, from his profile bio:

My interests include the combination of the power of the mind with modern quantum physics to obtain a unified world view as well as psychology. I'm currently doing independent research on the effect of brain waves on water clusters.

5

Yes, that seemed very "alternative" to me.

I’m having a jolly good laugh :D

If he's serious, he's going to have a seriously hard time getting his work taken seriously.

Augh! Whoever starred that comment -- now it makes it look like a statement of my interests!! Kill it! Kill it!

!!doubleflip/Just past the edit window!!

¡¡ʍopuᴉʍ ʇᴉpǝ ǝɥʇ ʇsɐd ʇsnᒋ＼(｀д´)／ᒋnsʇ dɐsʇ ʇɥǝ ǝpᴉʇ ʍᴉupoʍ¡¡

2:48 PM

It was me xD

Oh, and somebody else.

points at @Chemobot

Somebody mod else.

Hm

But I would have expected the screenshot of mine to be starred to.

Such a shame it’s not .__.

Another one:

How do you expect anything to be edible if it heats to $93~\mathrm{^\circ C}$ when added to water (e.g. saliva, stomach juice)? — Jan 1 min ago

It wouldn't make for an embarrassing star

@Jan Presumably he would plan to add it during preparation, and it would be allowed to cool before consumption?

Ouch...

Well, the hydrolysis of phosgene gives off -72.19 kJ/mol.

I guess it does not fulfill requirement #2, though.

2:59 PM

Separate packets of citric acid and sodium hydroxide, in equal molar equivalents of acid/alkali.

That sounds safer.

The NaOH should heat it right up. Would be pretty nasty swill to drink, though.

Or just add dry molecular sieve (3Å).

All that said, the OP is clearly fishing for product ideas to augment instant coffee. @ortho, you should hammer-close it for safety reasons.

Use your diamond Mjölnir for too broad, imho.

3:23 PM

Yes. Sorry for the delay, I was looking up mhchem's question.

I agree with too broad, since we don't do lists here.

However, it seems that while I was poring over the Red Book, four people already voted to close. Hence, no Mjolnir needed. :)

3:36 PM

Why is there no badge for ‘offering 10 krep in bounties’? :D

17

Q: Canonical MOs vs. Localized MOs: Do both represent reality in the same way?

In my understanding localized molecular orbitals (LMOs) are equivalent to "standard" molecular orbitals, often called canonical orbitals (CMOs—by the way, why are they called canonical?). We can produce LMOs by linear combination of CMOs and they represent the same physical state. I have two que...

quantum-chemistry computational-chemistry molecular-orbital-theory orbitals

3:51 PM

@Jan Seriously, that would be a great gold-level badge.

BTW, can I get you a cup of coffee? Some cookies? Uhm.. diamonds? Piles of cash?

;-)

Reputation for piles of cash sounds like a pretty good trade..

looks for answers to bounty

@orthocresol Might as well bring all the toxic incentives of the MMORPG world over to SE, right?

50

Q: Badge for bounties offered?

Would it be worth to to add a badge for offering a certain amount of rep over time (say 1000) towards bounties? It could be called the Sheriff badge. This sounds like a good idea to me now but I've been drinking. Update: With the introduction of the new bounty system, this request has become r...

feature-request badges bounty badge-request

16

Q: Can we have a badge called "big spender" or "seeder"?

If someone gives away lot of his reputation points for his questions (using bounties) he should get the badge "big spender" or "seeder" or "motivator".

feature-request badge-request

4:16 PM

Ping @penta

@Tyberius The "density matrix" used in the course of a HF calculation, as referred to by your link, is very different from the first-order reduced density operator, $\Gamma(\mathbf r_1)\equiv\int{\Psi\Psi^*\,d\mathbf r_2d\mathbf r_3\ldots d\mathbf r_n}$, whose matrix representation is diagonalized to generate natural orbitals. Personally, I would be inclined to call the former "density matrix" an "overlap matrix," instead, as it's what is used to probe the orthonormality of the canonical MOs. — hBy2Py 1 min ago

4:31 PM

@hBy2Py I’ll go for the piles of cash. An unemployed in need can always take piles of cash :D

4:42 PM

@hBy2Py Great answer to that question:

5

A: Badge for bounties offered?

I absolutely encourage posting while drunk. +1 to you. And (soberly, sadly) I'm not sure this would be the best idea -- you could get folks offering up easy 100 points on questions they haven't selected an answer to just to get this badge. Bounties are meant to be sort of a last resort incentivi...

5:00 PM

@Jan, the "reference" for the C-S-C bond angle: madsci.org/posts/archives/2001-06/993671808.Ch.r.html

;D

Yeah, I saw your comment.

I’m typing up my own answer to that atm btw, so hopefully the question stays open … (inb4 diamond Mjölnir)

I thought that as long as you have the question open in a browser, you can still submit your answer.

I can’t; Loong can.

You mean you're not Loong?

All these Germans look the same to me...

Do I have colourful squares in my avatar? D=

5:09 PM

user image

Close enough.

I should also insert some nitrogens and zincs into Loong's.

Yes, please do!

Who does this ring colouring remind me of … Oh yes NotNotNicolaou!

user image

Ok, I admit that was really lazy. ._.

:D

Hehe.. I have Nicolaou's book sitting on my table now..

I wonder if @Loong is reading his atm.

Answer given, if people now want to Mjölnir the question, go ahead ^^

5:22 PM

user image

It isn't that bad...

Is that Classics I?

(both the colouring scheme as well as that question you just answered)

Yeah.

pubs.acs.org/doi/abs/10.1021/jacs.6b02075

Talking about that kind of colouring

user image

After the tenth slide of his talk you get colour-blind.

I have Classics III — which reminds me I should bring it back home ~~into the Reich~~ from the lab …

5:49 PM

Another seven upvotes to homework answers of mine required for me to gain another silver tag badge. Where is my sock when I need him?

6:40 PM

@ortho, is Mart AWOL? I've been waiting for a response from him on this for nearly a week now.

@hBy2Py Yeah, Martin said he'll be busy for a while.

He'll be back next week.

@orthocresol ?

11

Q: Question about 'exotic potassium'

(I slightly edited the question after Klaus Warzecha's comment) I was reading a book called 'Hundred and Seven Stories of Chemistry'. There is a chapter about how the attributes of different elements can change in presence of enormous pressure and temperature. The book says in presence of enormo...

physical-chemistry analytical-chemistry electrons elements

Hexacoordinate-C

7:04 PM

Hey guys (girls too) I am doing a industrialization project at school and I need to create with my team a textbook about how to make the whole plant from the reactor to the smallest pipe to produce 50kT of aspirin every year.

And in one step we have to mix 30/70 of water/ethanol to use is as a solvant. The total mixture is around 5 m^3

I'm looking for great values of the enthalpy of mixing of this mixture (well water/ethanol in general at x% in ethanol) to design my heat exchanger

I looked at many things on the net but I'm quite confuse because there is not a lot things.

Do you know maybe a database with those kind of things. I thought water/EtOH mixture was well known

I can use Aspen Plus at school but I don't how I can do to predict it using Aspen so well if you have idea I would be glad thanks

Too bad Curt F. isn't pingable in chat; he might know of some good places to look.

@Hexacoordinate-C You might look in Perry's Handbook, e.g.:

amazon.com/Perrys-Chemical-Engineers-Handbook-Eighth/dp/…

@Loong Discussion above ;)

Hexacoordinate-C

Oh yeah I have it on my USB key I forgot hahah thank you @hBy2Py :D

@Jan I put it on my bedroom door just in front of me because this is beautiful

@Hexacoordinate-C :D

Hexacoordinate-C

It is on my door for two years now ^^

1 hour later…

8:17 PM

@Jan What does i.R. mean?

im Ruhestand i.e. retired.

Ah.. til

I guess we call them "Emeritus" around here.

The emeritus status is no longer granted in Germany due to reforms from the seventies (I think).

There are still some really old Prof. em. guys, but they’re dying out.

@Jan I worked out a synthesis for the molecule you suggested

would you be interested in looking over it with me sometime this weekend?

I’m somewhere this week-end, let me just remember where …

Oh yeah, on Saturday I’ll be in Rosenheim on a mobility-politics discussion.

8:36 PM

OK we'll see when we've got time. I've got to write it up properly anyways.

Do just post it, I’ll reply when I have time ;)

8:50 PM

By the way, what is it with professors writing emails at around midnight?

9:20 PM

OK

well i write all my emails around 3AM, so maybe professors are just sleep-deprived people too?

Must be a thing with chemists …

btw, when you suggested Darwinolide, did you have that in mind because you have a particular interest in these sort of diterpene natural products?

or just a new molecule you knew?

well actually, if u have 5min, I can show you my basic problem. I have a document, but a lot of stuff is left out

user image

so I thought of 3 general approaches and listed the problems with them (some steps are skipped over)

No, I suggested darwinolide because my seminar had darwinolide as a target molecule that us PhD students should devise a synthesis of :D

the big problem I am having is because the anomeric carbon is tricky

so the first approach won't five you any stereoselectivity (and problably won't work at all)

the second doesn't work becaus eI can't oxidize selectively

the third is best. It comes from an approach described by Overman et al.

but the issue is that the anomeric effect makes the initial furanoside ring closure favour the wrong diastereomer... so I will need to do an inversion. I would've liked to set it up so the anomeric effect gives me the right one, but I can't figure out a way so far.

I’m confident that the natural isomer is the preferred anomer, tbh. It just looks better if you build it ^^'

Your seven-membered ring-closing strategy is RCM? I think that’ll fail, unfortunately .__. Seven-membered rings are hard to make …

9:29 PM

I was worried about that too, but Grubbs' handbook of metathesis suggests it might work

of course, it can always be switched for a wittig

but I have done some molecular mechanics modelling and stuff on the two epimers

and the one in Darwinolide is equatorial, making it disfavoured by the anomeric effect (also, DFT single point energy is higher)

Hm, damnit D=

:(

my only idea was to get the wrong epimer, invert it, then pool it all with the right epimer

But is it somewhat stericly hindered so that it is less likely to attack acetate?

hmm

Overman's paper suggests the strategy works.

DOI: 10.1021/ja207727h

scheme 6

it's adjacent to t-Bu, so it would be much more hindered.

however, the smart thing about Overman's synthesis in that paper is that they use both epimers to make different molecules (hence the "divergent")

so I might need to figure out a whole new approach

Dunno, it might, work, it might not ^^

Nice paper you found, though +1

9:50 PM

thanks dude

Overman has been doing a lot of really interesting work on these diterpenes though

but I'd love to find an approach that works with the anomeric effect instead of working against it

Hello

Hi o/

\o

Mhmm some retagging event is due for a long time

@gannex Most amazing thing about this statement is that Overman is still at it

o/

@Mithoron I try never to close a question without having checked the tags or dropped a close vote.

The latter because if something is closed before answers materialise the tags no longer matter. (RemoveAbandonedClosed)

10:05 PM

yeah

have you seen his paper on coupling fragments?

I also considered that as an approach to Darwinolide synthesis (I want to use a stereoselective claisen rearrangement), but the problem is that it requres α,β-unsaturated ketones

10.1021/acs.accounts.6b00284

I've been out of chem for like 7 years

I don't even have journal access any more

awh

if you're interested I can upload the PDF

(sorry JACS!)

*coughsScihubcoughs*?

I mean, no-one’s seeing you use it, are they?

(I’m pretty sure I used that site over at work … O:))

Nah. I have to get my non-chem work done :/

aw not NON-CHEM

10:11 PM

:D

although to be quite honest, non that I'm starting to learn pchem properly (finally), physics is looking really enticing

Always do it with calculus

:D

yeah. the problem is a lot of the classes in the beginning of my chem degree skimmed over a lot of the calc. and now my skills are rusty

plus HS where I live doesn't care about math

I'm trying to catch up now. I used to be too much of a lazy student. Hired a math tutor and stuff

There’s a life outside of chem?

@Jan I didn't say that. I just have a job outside chem

10:18 PM

A job is life, is it not?

Sometimes

I did use chem at work once to make fun of someone who thought they were allergic to msg

@Jan yeah, but it only exists to serve chem.

10:58 PM

Ooh, I used up all my close votes for the day =D

11:38 PM

hey, should I be editing questins and stuff like you guys do?

I've only ever contributed by submitting answers and questions

but I notice all that meta stuff also seems to be important around here

should I be looking into meta?

To quote the first (and only) rule of Finnish saunas in a slightly different way:

> Do as you wish as long as it feels good.

2

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Transcript for

Mar '1721

The Periodic Table

Haikus are awesome / Chemistry's even better / So pull up a chair

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