The Periodic Table

pentavalentcarbon

03:00

If I had been a Google Summer of Code mentor I would have been more involved in the Python/CJSON stuff that's happening right now.

hBy2Py

Memory check ... is he at Pitt, too?

pentavalentcarbon

His office is maybe 4 doors down from mine.

hBy2Py

Is he faculty, though?

pentavalentcarbon

So we chat every now and then. He's my advisor for some bureaucratic thing I have to do.

Yes.

hBy2Py

Are you/he involved with PQR?

pentavalentcarbon

03:03

I am not involved in PQR. He is the lead author of PQR.

I wish I was involved but there's only so much time in the day.

Some CS undergrads did most of the front-end stuff but he did all the chemistry: github.com/pittquantum/workflows

hBy2Py

@pentavalentcarbon I haven't really looked closely at it since it went live. It seemed like it was impending for a terrifically long time, and then I've never given it a close look since it went up.

pentavalentcarbon

There are still some bugs, but AFAIK it's "done" and has been for probably a year.

"Done" in the sense that it meets their initial teaching goals.

hBy2Py

Hm.

It doesn't look like it does orbital isosurfaces...?

pentavalentcarbon

No, no orbital information present. I'm not sure if that was part of the plan...maybe?

In that case it isn't done. But I guess it's possible, the hard part is making the web interface with clicky buttons and stuff.

If you like chemical databases, there's also this one which is relatively new: vergil.chemistry.gatech.edu/bfdb_private/bfdb/cgi-bin/bfdb.py

hBy2Py

I like the idea of them, but I've not ever really been in a situation where I've found them useful.

Or, at least, where I've figured out how to make them useful for what I'm trying to do.

pentavalentcarbon

03:14

I've used CCCBDB quite a bit, and if you don't know about it, I would check that one out first. Experimental and calculated values for many properties. Good for reference data.

hBy2Py

I'm a vaguely recovered completionist, so databases like that have something of a siren song to them... "come closer, one day I may have ALL THE CHEMICALS!!!"

8

A: Community Promotion Ads - 2016

:-)

pentavalentcarbon

That one is complete in terms of properties, IMO, but definitely not in terms of chemical space...only a few heavy atoms.

oooooooooo

hBy2Py

I have a couple of others that I'm hoping to have time to work up community ads for in the 2017 cycle.

pentavalentcarbon

Like, if you want a quick comparison of the MP2 vs. CCSD harmonic frequencies of something, you have to agree it's pretty good for that.

Or other basic stuff that they just throw the book at.

hBy2Py

<nod>

I think mainly I just don't have a gut feel for what all is in there, so I don't know when to crack it open.

And browsing through it without being in a situation where I'm looking for something specific makes it hard for me to internalize the categories of content.

pentavalentcarbon

03:19

I know what you mean. Frankly most of what you want probably isn't in there anyway.

hBy2Py

<nod>

And while I've run a lot of computations, I'm still not fluent enough to be confident that what I might find would actually be valid to compare with whatever other thing I've got on hand.

And, really, I'm more into the methods and tools than specific systems themselves, so I need to be running the computations myself a lot of the time anyways.

pentavalentcarbon

For CCCBDB in particular I can vouch for it, I've always been able to reproduce their numbers exactly.

hBy2Py

Nice.

pentavalentcarbon

Can't say that for other literature.

hBy2Py

Is it all generated from Gaussian (or some specific other package), or do they use a variety?

pentavalentcarbon

03:22

I'm pretty sure they use Gaussian.

hBy2Py

There are a surprisingly large number of details one has to get right in order to exactly reproduce calculated values.

I tend to get a little OCD when I go back over my input files.

How's your work coming?

pentavalentcarbon

Sometime you should download this, run the Python script, and question your use of ORCA: github.com/berquist/energy_comparison_hf

wait, ORCA does ok, nevermind

But still. I think this is a generalization of chat.stackexchange.com/transcript/message/33702291#33702291.

hBy2Py

Huh - reproducibility is easier with other packages, you mean?

pentavalentcarbon

This is going to be formatted really poorly, forgive me; the point is that it is very difficult to compare numbers for the simplest quantity (total energy) across different packages no matter how many knobs you turn.

HF
-559.8273432575 GAMESS
-559.8056719280344 CFOUR
-559.8056719011 Q-Chem
-559.805671885101 MOLPRO
-559.80567187 ORCA
-559.805671844309 NWChem
-559.8056717655093 Psi4
-559.805664133182 DALTON
CCSD(T)
-560.028878142881 CFOUR
-560.0288778584758 Psi4
-560.0288702285 DALTON
-560.02767491 Q-Chem
-560.027674904 ORCA
-560.0276748168242 NWChem

hBy2Py

Ohh, right, right, gotcha

pentavalentcarbon

03:29

That looks better than expected.

I'll let you decide what those numbers mean.

hBy2Py

The details of the implementation matter, basically. Absolutely.

And you're sure the basis sets are all identical?

With HF especially -- I would think there's only one STO-3G, but... do the differences fall along spherical vs cartesian basis representations, maybe?

pentavalentcarbon

It can't. Do you know why?

hBy2Py

Which "it"?

pentavalentcarbon

Basis set differences due to Cartesian/spherical.

I'll give you a hint:

hBy2Py

Oh, I figure the two representations are mathematically equivalent -- but perhaps the math for handling them numerically (integrating them, mainly?) performs differently when computerized?

pentavalentcarbon

03:34

---------------------
BASIS SET INFORMATION
---------------------
There are 5 groups of distinct atoms

 Group   1 Type C   : 6s3p contracted to 2s1p pattern {33/3}
 Group   2 Type N   : 6s3p contracted to 2s1p pattern {33/3}
 Group   3 Type O   : 6s3p contracted to 2s1p pattern {33/3}
 Group   4 Type S   : 9s6p contracted to 3s2p pattern {333/33}
 Group   5 Type H   : 3s contracted to 1s pattern {3}

No, Cartesian always gives lower energy than spherical, so that would be a difference. I'm asking why it doesn't matter here.

hBy2Py

@pentavalentcarbon <grin>, see, I didn't even know this. Major disadvantage for me of not having undergone any tutelage with a practitioner in the field.

No, I have no clue why it doesn't matter.

From the hint... something to do with how the bases are contracted?

pentavalentcarbon

I don't have d functions.

hBy2Py

Googles desperately for the <shrug> emoji

Why would d be harder than p?

pentavalentcarbon

I quote Frank Jensen:

> The sum of lx, ly and lz determines the type of orbital (for example lx + ly + lz = 1 is a p-orbital). Although a GTO appears similar in the two set of coordinates, there is a subtle difference. A d-type GTO written in terms of the spherical functions has five components (Y2,2, Y2,1, Y2,0, Y2,−1, Y2,−2), but there appear to be six components in the Cartesian coordinates (x2, y2, z2, xy, xz, yz).

hBy2Py

Mmm, that rings a bell.

pentavalentcarbon

03:40

There are more functions in the Cartesian representation than the spherical representation...starting at d functions.

hBy2Py

5 vs 6 for d .. what, 7 vs 9 for f, is it?

pentavalentcarbon

7 vs 10 for f

hBy2Py

That always did bother me a bit, actually -- it seems like that has to mean that the Cartesian representation is overspecified somehow... maybe?

pentavalentcarbon

So, the point is that no matter whether a program uses spherical or Cartesian functions, I remove that from the equation because the representation of s- and p-type AOs is identical in both coordinate systems.

> Furthermore, the use of only the spherical components reduces the problems of linear dependence for large basis sets, as discussed below.

ding ding ding

hBy2Py

It's reminiscent of how three-space is described with four Miller indices when dealing with hexagonal close-packed crystal structures. That always bothered me.

Uggh - so Cartesian gives lower energy than spherical because it has more functions, and thus more variational flexibility?

pentavalentcarbon

03:43

Unfortunately I know nothing about the solid state so the analogy is lost on me.

Yes.

hBy2Py

Even though they're not fully properly independent functions.

Ew.

!!flip/Cartesian

pentavalentcarbon

I bet things like reaction energies are still ok, but generally speaking, this is a trap with sharp pointy things in it.

Chemobot

(╯°ਊ°)╯︵Ɔɐɹʇǝsᴉɐu

pentavalentcarbon

Very bad.

hBy2Py

Which packages are based on Cartesians? Any of the majors?

pentavalentcarbon

03:45

Oh so you'll really like this then.

Ignore specific packages for the time being.

hBy2Py

hahaha

k

pentavalentcarbon

There are certain basis sets, 3-21G and 6-31G (not 6-311G) in particular, dunno about STO-nG, that were optimized to be used in the Cartesian representation.

So, when you use those (crappy) basis sets with packages that only work in the spherical representation, you're forced to get the wrong answer.

hBy2Py

POPLE!!!!!!!

pentavalentcarbon

They had limited computing power. Those basis sets are so deficient for multiple reasons.

hBy2Py

Thank goodness for Dunning, Ahlrichs, et al. And for modern computers.

<nod>

pentavalentcarbon

03:48

Ahlrichs is lit, those are my go-tos. Dunning is tough because of how they're constructed.

But those and Frank Jensen's sets and the various ANO sets are all designed to be used in the spherical form.

hBy2Py

Seems like Dunning is best for basis set extrapolation, since that's what they were designed for (if I'm remembering right... the ccVnZ sets or whatever)

pentavalentcarbon

Yes.

hBy2Py

Related: I bought a used copy of this book for relative cheap:

amazon.com/Quantum-Chemistry-Challenge-Transition-Coordination/…

Published in 1986

pentavalentcarbon

Dunning for extrapolation of the correlation energy, Jensen for extrapolation of the mean-field energy, but you can do it with other basis sets too.

oooooooo

hBy2Py

So. Painful. Reading them trying to cope with metals with 1986 computing power.

pentavalentcarbon

03:51

All the old literature on complicated stuff has hand-constructed basis sets, and lots of CISD calculations...

We do better now.

hBy2Py

I have a soft spot for classic scientific books... I bought the whole set of Herzberg's classics

(atomic spectra, spectra of diatomics, IR/Raman of polys, electronic of polys)

pentavalentcarbon

I have...none of them in hard copy, I have some other gas-phase spectroscopy thing.

But my electronic copy of the diatomics one has been super useful for me.

Great reference.

hBy2Py

If I ever get anywhere substantial with opan, I figured the IR spectra volume would be mega-handy.

Though, NIST Chem Webbook and/or CCCBDBDBDDBCBDB would probably be equally or more valuable.

pentavalentcarbon

bwahahahaha

Mmmmm, I don't think either of those will be as useful as you hope.

hBy2Py

Oh... no anharmonic constants?

pentavalentcarbon

03:56

IIRC no.

wait...

cccbdb.nist.gov/anharm1x.asp

I can't find any molecules with the data though.

But what you actually want is to just run some other program yourself and use that as a reference.

hBy2Py

Hm... as long as multiple softwares agree, then the method is probably solid?

pentavalentcarbon

Yes.

hBy2Py

I guess .. that's where Webbook and Herzberg would come in, though, is comparing to actual experimental x and y spectroscopic values.

pentavalentcarbon

Your best free choice is GAMESS. I don't remember if it'll do VPT2 but it does VSCF.

hBy2Py

IIRC NWChem does VPT2

pentavalentcarbon

04:00

Yes, they're experimental references. Or compared against some harmonic frequencies if you don't want to do the calculations yourself.

hBy2Py

One of them did. Firefly, maybe...

pentavalentcarbon

Ok, didn't know that.

hBy2Py

Gaussian does, obviously, with Barone dominating the "virtual spectrometer" space.

pentavalentcarbon

Firefly doesn't run on my computers because of it's 32-bit-ness.

hBy2Py

Oh.

Crud. Won't work on any of mine, either.

pentavalentcarbon

04:01

Gaussian is slowly getting their lunch eaten.

hBy2Py

I'm not surprised. Too many people working on too many other options, many of which are free, or considerably cheaper.

And even if G's customer support is amazing, still, sooo many people just post their HALP FX MA GASSIN INPT to CCL instead.

pentavalentcarbon

That's just because of ubiquity. If everyone was using NWChem or some other package the same thing would be happening.

hBy2Py

Mm, point. Have been using COMSOL at work -- their tech support is terrific, but yeah, if I went searching, probably ResearchGate et al. are full of HALP FX MA COMSL SIM, in much the same way.

pentavalentcarbon

I'm glad I don't subscribe to CCL anymore and I turned off ResearchGate spam.

hBy2Py

Most of CCL I ignore. Occasionally there's an interesting article or topic that comes up that's worth dealing with the cruft.

We're mostly using ResearchGate as a publication archiving service. Posting talk slides and stuff.

pentavalentcarbon

04:09

Well, I told myself I'd update my resume/CV today, and all I've done since coming home is hang out here.

hBy2Py

Hehe, I had grand plans of starting to pull together the computational data for my answer to this old question:

14

Q: What is the chemical structure / hybridization of sulfuric acid?

I was looking at the chemical structure of $\ce{H2SO4}$. Intuitively, I would have expected this molecule to be square planar in accordance with $p^2d^2$ or $sp^2d$ hybridization, but instead it is shown to be in a tetrahedral geometry consistent with $sp^3$ hybridization. Why is this? I gue...

But, here I am instead, as well.

user228700

Is anybody here familiar w/ the properties of the nuclear force (a.k.a string force) ?

user228700

in The h Bar, 2 mins ago, by Kaumudi

> "The nuclear force is not a central force."

pentavalentcarbon

You use thread to tie the nucleons together.

hBy2Py

(psst - he's totally joking)

user228700

04:12

What does that (my linked message) really mean?

hBy2Py

Nope, no idea.

Seems like something you should be asking on Physics.SE. :-)

user228700

@pentavalentcarbon Say, who makes this thread? :-)

user228700

@hBy2Py I have. Only, not many people are online.

pentavalentcarbon

From the cotton loom I carry around with me

I think that statement is wrong though, it's one of the fundamental forces.

hBy2Py

@Kaumudi <smacks forehead> You were quoting your own chat. Sorry!

pentavalentcarbon

04:14

@hBy2Py It probably involves QTAIM, right?

hBy2Py

Are you referring to one or the other of the strong nuclear force or the weak nuclear force, or something else?

@pentavalentcarbon Indeed. All four S-O bonds are charge-shift bonds.

So I'm pretty sure that hybridization is out the window entirely.

user228700

No, no, it's very much correct:

user228700

> "The force depends on whether the spins of the nucleons are parallel or antiparallel, as it has a non-central or tensor component. This part of the force does not conserve orbital angular momentum, which under the action of central forces is conserved."

user228700

@hBy2Py Lol :-)

user228700

Okay, perhaps that's a bit advanced and I should just leave it at "The nuclear force is noncentral" for now.

pentavalentcarbon

04:17

I guess I mixed up fundamental and central. I don't know anything about this except for maybe parity violation.

Also once it hits 11 PM I turn into a pumpkin.

hBy2Py

<nod>, I need to finish these dishes and get to bed.

user228700

Ah, I see.

pentavalentcarbon

o/

user228700

Well, the day has only just begun over here! Goodnight and many thanks! :-)

hBy2Py

@Kaumudi I love how global SE is. :-)

Good luck finding the answer to your question!

user228700

04:18

Me too :-D Oh, thanks.

hBy2Py

Goodnight / Have a good day

user228700

Thank u :-) Also, for those who are curious:

user228700

> "A central force is a force that points from the particle directly towards (or directly away from) a fixed point in space, the center, and whose magnitude only depends on the distance of the object to the center."

user228700

The strong force doesn't depend in the distance b/w two nucleons. Hence, it's not a central force.

user228700

05:53

I've a quick question again!

user228700

I learned that the inductive effect that an atom/group A exhibits does not depend upon the the atom/group to which A is attached.

user228700

Rather, the inductive effect of A is determined relative to hydrogen.

user228700

This definition would imply that in a molecule such as $Cl_2$, both Chlorine atoms do show $-I$ effect, but that these effects cancel to result in zero net dipole moment.

user228700

Another user has argued against this definition by quoting Wikipedia:

user228700

> "In chemistry and physics, the inductive effect is an experimentally observable effect of the transmission of charge through a chain of atoms in a molecule, resulting in a permanent dipole in a bond."

user228700

06:07

He says that since no permanent dipole moment exists in molecules such as $Cl_2$, that the Chlorine atoms do not exhibit the inductive effect (as opposed to the effect due to both of them being cancelled)

user228700

What is the correct way to think about this? Also, dyou think it will be good to ask this question on the main site, instead?

user228700

11:21

Yeah, for the whole time I'm awake, this place is dead.

Hexacoordinate-C

11:32

@zhe I think you forgot a carbon their chemistry.stackexchange.com/a/62991/15235

Hexacoordinate-C

11:44

For me this is what you draw

orthocresol

11:57

@Kaumudi My first thought is that this is really splitting hairs.

My second thought is that it is not always explicitly mentioned, but an inductive effect is always a comparison between two different substituents. It need not be hydrogen: for example, you can say that fluorine is more electronegative than iodine, exerts a larger -I, and therefore CF3COOH is more acidic than CI3COOH.

Hydrogen is usually the reference substituent, though.

As such, you need to make clear what you are comparing Cl2 with.

user228700

Nothing, really...

orthocresol

It makes no sense to talk about the "inductive effect in Cl2" when you're not comparing it with anything. For example, if you were to compare it with HCl, you would either say that hydrogen has a +I effect relative to chlorine, or chlorine has a -I effect relative to hydrogen.

That's my stand on it, at least.

user228700

Okay, so as such, there is no inductive effect in Cl2?

orthocresol

I'd go so far as to say that "inductive effect in Cl2" is not a well-defined term :)

But yeah, it's closer to "no inductive effect" than "inductive effect in both directions cancels out".

user228700

Damn :-/ OK.

user228700

12:03

Dyou think I should ask at the main site?

orthocresol

Sure, why not

user228700

Alright, that I will do. Thanks :-)

DSVA

Imo inductive effects are defined compared to hydrogen bond to a carbon. You can use the concept for other "central atoms" too, but it might not be very clear.

Chemobot

12:19

23

Q: Why does ice cream make soda fizz?

I've noticed that adding a chunk of ice cream to soda makes the soda fizz slightly near the soda-ice cream interface. I thought it was a physical effect due to the temperature, but adding ice has no effect. It still can be a physical effect due to solubility, or it may be a chemical effect. I'...

physical-chemistry solubility everyday-chemistry

hBy2Py

@DSVA, I accidentally pinged Melanie on this last night instead of you:

10 hours ago, by hBy2Py

@pentavalentcarbon @Mel I keep a running list of run descriptions as comments at the top of my input files, and just number the input files sequentially. It bloats the files considerably, but I always have a full history of that series of computations by looking at the highest-numbered one.

DSVA

@hBy2Py do you mean a list of that whole series, even if it's different calculations? That's a nice idea but I don't know how practical this would be for me, since I'm producing a lot of those with several scripts and I'm using "keywords" in the file name to tell my scripts what kind of analysis should be done

Martin - マーチン

12:53

@pentavalentcarbon I'd really appreciate your input on this.

<-- flies away

hBy2Py

13:13

@DSVA ... list of that whole series, even if ... Yep.

I don't have a lot of post-processing to do, so the simple filename is fine for me.

*... "keywords" in the file name ... * If you're working on Linux (or similar), it would probably be possible to parse the file contents for the keywords... but yeah, probably much more complicated than just inspecting the filename.

Or, well -- you could put together your own keyword syntax to include within the comment structure... like for ORCA, where comments start with #, you could make it ~shebang style:

# This is a regular comment
#@freq
# The above triggers a frequencies post-analysis

or somesuch

Feeds

orthocresol has made a change to the feeds posted into this room

DSVA

13:35

@hBy2Py that's a pretty good idea. I guess my system will develop more in the future. Sometimes I'm running more than 100 calculations at once, really important to be able to read out the data at least somehow automated.

hBy2Py

13:56

@DSVA Yeah, I have grand visions of automating my data analysis, too. Other than cclib and a couple of others, there don't seem to be many packages out there.

And I haven't found that those that do exist match all that well to the data parsing I need.

It may just be something that each computationalist has to put together ~individually.

DSVA

yes it seems like that. And I really don't get it. NWChem for example is running very nice and they put a lot of effort into that but there's no good software for producing input or reading output

and GaussView is pretty nice but it's >10 years old so a lot of stuff is missing

And documentation about output files basically doesn't exist for both:-/

Jan

15:47

Something’s telling me I’ll lose a bunch of rep due to ‘user was removed’ soon.

M.A.R.

15:58

@M.A.R. good question and you're welcome! — Nullarbor 3 hours ago

Appearing out of nowhere and after an upvote.

@Ortho can you please investigate?

If you have time, of course

Jan

Weird things going on on chemistry ô.o

DSVA

what's the problem here?

orthocresol

16:14

@M.A.R. Thanks, I'll look into it.

@DSVA Serial upvoting.

@M.A.R. This person's first rep gain was due to an edit, adding mhchem syntax to a post. I usually find that a little intriguing; it's either 1) the guy is someone we really want around here 2) it's some kind of sock

I'm leaning towards the former right now, as there's no evidence for sockpuppetry; maybe if there is some kind of serial voting going on, we will tell the guy, but as far as I can tell there's nothing unscrupulous here.

Jan

@M.A.R. are you also a ‘serial upvote target’? I mean, my questions seem to be …

orthocresol

16:36

@Jan Doesn't seem to be: chemistry.stackexchange.com/users/7448/m-a-r?tab=reputation

Jan

Not really. My reputation tab looks worse xD

orthocresol

Don't you mean better ^^

Too good to be true.

If it's all by one person, the serial voting script will probably reverse those; it runs overnight, so just give it a day or so.

Jan

Ah good, so I can still collect 20 rep to hit 0.2 krep today.

(Yes, @Loong, I’m using ‘0.2 krep’ just because! x3)

orthocresol

Metacresol, India

560 2 18

everyday-chemistry homework inorganic-chemistry oxidation-state bond electronic-configuration organic-chemistry

...

Jan

Now that does seem like attempting impersonation ô.o

Loong

16:43

renames account to "3-methylphenol"

2

orthocresol

inb4 "ipsocresol"

Jan

That would be impersonating both you and @pentavalentcarbon

orthocresol

Hahaha :D

o_o

Loong

!!img/bromocresol green

Chemobot

Jan

16:52

Fun fact: I asked 21 questions on the site and got 20 question upvotes between going to bed yesterday verylatenightearlymorning and late afternoon today xD

Obviously, the serial upvoter missed a question 8D

Loong

17:17

!!img/2-({(3E)-4-[4-(dimethylamino)phenyl]but-3-enoyl}oxy)ethyl methyl benzene-1,4-dicarboxylate

Chemobot

No result found.

Loong

as expected

paracresol

XD

@Loong Hallo o/

Jan

@Loong Was that the ‘halp me naim mai moleculez cheezburgaz by IUPCA pls kthxbai’ question?

paracresol

@Jan Because I'd already upvoted it before ._.

Jan

17:20

!!img/ipsocresol

Chemobot

Jan

@Chemobot … ?

paracresol

@orthocresol That was not my sock account, believe me [ Its got a better name ;) ]

@Jan ipsocresol?

Jan

36 mins ago, by orthocresol

inb4 "ipsocresol"

paracresol

"Metacresol" How very un-original -_-

Loong

17:26

@Jan Yes, that's one of it. However, OP doesn't look so much like "halp pls kthxbai". He made a few awkward edits and appears to be rather helpless.

paracresol

@Loong Does that require suspension? 3;)

Jan

To be honest, I can’t really tell. The fine line between ‘halp pls kthxbai’ and somebody who will actually be thankful for hints is rather hard for me to see …

Mithoron

17:47

@Jan I can make much more than I3-

But longer chains are less stable indeed

Loong

@Jan chat.stackexchange.com/…

Mithoron

@Loong :D

Hexacoordinate-C

18:06

Hey

@Jan thanks to me today you must won 200 reputations

paracresol

@Hexacoordinate-C Salut o/

Jan

@Hexacoordinate-C Oh you were the serial upvoter?

Hexacoordinate-C

Yep

paracresol

@Jan No... 'twas me ;P

Hexacoordinate-C

To improve you gold bages and mine ^^

Jan

18:07

@Hexacoordinate-C *flags for @ortho, @loong*

paracresol

Ah, @Jan's a stickler for rules @Hexacoordinate-C. It was nice knowing you o/

Loong

sigh

paracresol

:D

Hexacoordinate-C

Wow wow wow I understand nothing lol

From flags for ortho, loong

What should I understand ?

Jan

@Hexacoordinate-C You missed a question, btway ;p

Loong

18:09

413

Q: What is serial voting and how does it affect me?

I just noticed that I lost a bunch of points from my reputation score, and I used the "reputation" tab on my user profile page to try and track down the cause. During my investigation, I noticed there was an unusual event of type "reversal". In the normal place of a question title, it says "voti...

support faq reputation voting serial-voting

Hexacoordinate-C

@Jan I wasn't sure, share it I'll do it in 5 hours ^^

paracresol

@Hexacoordinate-C Jan's not going to go easy on you, just because you upvoted 20 of his questions. He's pinged the Mods...and now they'll be after your ~~blood~~ account. So in the eventuality that you get suspended... I'm saying 'bye' in advance ;) o/

Hexacoordinate-C

Oh

I didn't know that was forbidden

It was for a good cause

Next time I'll upvote on question by people every day

Jan

Just upvote good questions (and answers) when you stumble across them.

Hexacoordinate-C

Yours are good

Mithoron

18:17

Just what I wanted to say ^^

orthocresol

Still...

Jan

@Hexacoordinate-C Okay then let me rephrase:

> Just upvote good questions (and answers) when you stumble across them.

Hexacoordinate-C

Upvote

(pick one)

It's clear and shows research effort
The question is plain awesome (in case of fun questions, this can go either way)
The question is useful to others

I also need to edit 500 posts

Loong

@Hexacoordinate-C This is not a grinding game.

Hexacoordinate-C

@Loong I've nor the time neither the skills to do it as well everytime. And don't worry I won't do it :)

DSVA

18:30

but...but the ~~e penis~~ internet points!

Jan

@DSVA I know, they’re shiny, glittery, rainbow-coloured, sparkly and contain unicorns and pegasoi but … they’ll break and cry if you abuse them Y___Y

DSVA

:-D

Loong

If you really want to engage in repetitive tasks for virtual internet points, wait until Winterbash 2016.

Hexacoordinate-C

What is that ?

Also I really don't care about my badges. I hope my questions and my answers if they are well received not depend on that.

Loong

This was 2015: stackpromos.com/promos/16/winter-bash-2015

Winter Bash 2015: Hats Off

Pops on January 6, 2016

It's a new year, and another Winter Bash is behind us. Let's relive some of the highlights, and finally get to the bottom of the mysteries of the secret hats, before we close the 2015 (year)book for good!

Hexacoordinate-C

18:38

Then I'll need to put my face too haha

Loong

I expect that the countdown will start on 1st December.

Jan

Thaaa~t would make sense.

Loong

It did so last year.

Hexacoordinate-C

It made me think about a Feynman answer about a girl at university or something else who sent him a letter or a mail to tell him, because of him she not succeed (I don't remember) and he answered something like it was not because I won the Nobel Prize that he wasn't able to make a mistake even for low level of physics (compares to him) and he advised her to check on other references.

Is there a name for this representation of a molecule ?

orthocresol

electrostatic potential map

Hexacoordinate-C

18:50

thanks

orthocresol

19:09

Hmm, I wonder if anybody here is willing to take on a nasty group theory task.

I'm thinking of posting it on main site, but I don't even think it's a very useful question.

The issue is whether $(R_x,R_y)$ transforms as $\mathrm{E_1}$ or $\mathrm{E_3}$ in the point group $S_8$. I have different sources telling me different things

Jan

That moment when you realise you defined a macro in your LaTeX document that introduced an extraneous space … that wasn’t gobbled because it was in curly brackets …

Jan

20:18

Speaking of gamification … there I was, frantically refreshing to get a late answer review but not noticing that @ortho had deleted the answer within minutes of it appearing xD

Loong

mod abuse!

Mithoron

Fastest gunslinger ;D

Loong

undeletes the answer, flags it again

orthocresol

20:40

@Jan You have no hope. Give up now and you will be spared from suspension

Jan

-1

Q: Why is that n-Butyllithium is a better reagent than Propynyllithium to synthesize lithium cyclohexylamide from Cyclohexylamine?

I believe that multiple Sn1 reactions are going on as we do not have a strong nucleophile and we are going to form carbocations. I believe that because a carbocation on n-butyl is more stable than a carbocation on propynyl, using n-butyllithium would be a better reagent. I am not sure whether my ...

organic-chemistry synthesis

How hard can it be to synthesise lithium cyclohexylamide …?

@orthocresol I never had any; I know. I surrender 5 krep.

orthocresol

@Jan ouch...

Michael Harding

I was thinking.

How can you use things like carbon nanotubes in drug delivery?

E.g. targeted cancer treatment.

Jan

Have a needle that extends to a carbon nanotube and make sure you push it into the correct vein intravenously 8D

Michael Harding

Because they can transport a drug through the body without it having negative effects on other cells, but once it reaches the desired cell, what happens?

Jan

20:51

(Sorry, just being silly ^^)

Michael Harding

Does it bind with the cell somehow? Like some sort of inorganic structure designed to bind with a specific protein on a cell?

orthocresol

It might be, but I don't know. Never read about these before

Michael Harding

I can't find anything on stack exchange :'(

Jan

Isn’t it still in the purely hypothetical stage?

Michael Harding

Idk Jan, I was just thinking about it in class today xD

We were introduced to cisplatin.

And I was just thinking about targeted drug delivery.

Jan

20:55

I'm literally gong to fail this class if you don't tell me. — Barbu 1 min ago

DSVA

The problem with all those targeted therapies is that it's not the big challange to get the "container" there (assuming extracellular targets), it's the release

Michael Harding

Yeah, exactly

DSVA

if you use a buckyball or some polymer and you got the drug on the inside: how does it get out? Well, you usually use bonds which somehow get hydrolyzed and then you release the drug, but how to get certain they don't release before?

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