last day (2098 days later) » 
18:00 - 23:0023:00 - 00:00

6:19 PM
Welcome to chat for: Chemistry
This is a general discussion room, but please feel free to create more subject-specific rooms (a single room with every possible discussion isn't very helpful)
For playing with chat features:


Where you can play with chat features (except flagging) and ch...
and remember; please read the FAQ ;p)
Welcome welcome welcome!
Hmm, didn't notice this was here, made one of my own
It's up!
Q: Why do atoms generally become smaller as one moves left to right across a period?

timothymhIt seems to me that the addition of electrons as you move across a period would cause an atom to become larger. However, I'm told it gets smaller. Why is this?

First question
6:25 PM
(And I just asked the first question!)
It took us long enough to get this ball rolling.
Finally in Beta. Feels good!
@timothymh Its because you have more protons 'pulling' on the electron cloud IIRC
@LordStryker I'd probably just tag or something
and seem fraught with peril on this site
@NickT Seems straightforward enough.
I second it.
When won't they apply though
@LordStryker I know.
6:28 PM
Any thoughts on homework questions?
wonderful, we're up and running!
hi all
They seem like they'd be the Chem.SE equivalent to or on EE.SE
@Fx 'lo!
@Andrew Homework is fine so long as you've made an effort
There are presently two Chemistry.SE "main" chat rooms. We should decide on one, and close the other.
6:29 PM
and your singular question is clear
@nhinkle I made the other, didn't notice this was made (automatically?) I was just trying to be more creative
@nhinkle I vote for camping out right here.
I like the name of "The Periodic Table - pull up a chair" better than just "Chemistry" (it fits the tradition of each site having a creatively named main room), but it appears most of the activity has been here so far.
This room is populated.
Let's change the name of this room then. I'll see if I can merge the other room into this one, and if not, I'll freeze it.
A mod can come in and modify this room later?
Okay so, meta, but how do we become a mod?
6:30 PM
@LordStryker @nhinkle is a mod (blue text)
I'm a mod on another site, which makes me a chat mod everywhere. I'm not a mod on Chemistry.SE though - it's too young to have mods yet.
Chat.SE doesn't care though?
@NickT me too, me too! :)
The SE Team will appoint Pro-Temp mods sometime after the site enters public beta. Then once the site eventually graduates, there will be an election to determine permanent mods.
@nhinkle you can't merge rooms, but you can delete it
it has not yet had any content
6:32 PM
Hmm, anybody know how to make equilibrium arrows?
@Fx I just froze it.
well, it did not have any content until you posted your message :)
I can only come up with "<->" right now
@Fx port the name/description here :P
Will we get laTeX code integrated for SE:Chem?
6:32 PM
Is everyone OK with renaming this room then?
@nhinkle I vote yes.
@LordStryker it can be enabled if requested. Post it on meta and the team will decide. Seems appropriate for this site.
A: Which plugins for chemical formulas do we need?

FabianMathJax, which is already used by many SE sites supports the mhchem extension meant for typesetting chemical formulas like H2O or [AgCl2]- using simple syntax like \ce{H2O} or \ce{[AgCl2]-}. We'll likely be using chemical formulas very often, so a simple way to enter them would be very useful. A...

room topic changed to The Periodic Table: General chat for Chemistry.SE, pull up a chair! (no tags)
@Fx but now I'm not room owner :P
6:36 PM
Shame that I'm not actually in a chem class right now, and my chem engineering class this term is mostly statistics. I'm taking pchem in the fall though... so I'll surely have questions then.
Q: LaTeX code for submissions

LordStrykerI ask we get LaTeX code enabled for our community. I am a computational chemist who regularly deals with mathematical equations. Being able to communicate these equations in a professional way such as LaTeX is rather necessary. Also, LaTeX is good for (with proper modules) chemical equations, ...

@NickT feeling better?
I do find it amusing that this site opened 2 hours after my Pchem final
@Fx yay, italics
Anyone care to add me?
6:37 PM
@NickT Haha
@NickT you take what you can when you can't have blue :)
I'm still working on my take-home part though, but I'm mostly just screwing around with making it look nice
i invited my little brother! he's a pharm student
6:37 PM
@Aarthi yeah babe, that's what I call chemistry :)
Take-home pchem exam?
rofl maybe? Pitt has been having troubles of late
Based on this, it appears that LaTeX is already enabled
Q: How does NaCl maintain its crystalline structure?

soandosMy understanding is that NaCl is an ionic compound, in which Cl becomes (effectively) Cl$^-$ and Na becomes Na$^+$. So I understand why I would get a "sea" of particles that would stick together. But why does the above mean that it will have a face centered cubic structure with the ions held in ...

I would've given my seargent-welsh periodic table for a take-home pchem exam
6:38 PM
@nhinkle On what?
@timothymh look at the question. Soandos used the LaTeX formatting, and it worked
@LordStryker part of it is, but just because it's pretty much required to use a computer for some of the integrals
They don't let you use calculators that can do integrals, but send part of it home?
@nhinkle I see.
6:40 PM
@nhinkle In Quantum we used Mathematica but we had to bring our laptops to the exam.
well, Sibling is in Orgo2 right now
but he's so smart
he's smarter than I am, tbh
But then I'd like to see anyone solve those 1- and 2-electron integrals by hand.
and he's super good at tutoring other students
I'm curious to see how they do the exams for the statistics class I'm in right now... we use Excel and Statgraphics and such all the time, but they don't like us having computers for exams because we "might cheat"
@nhinkle numeric integration on calculators is fraught with peril
6:42 PM
maybe just a personal note: while everyone's very happy about Chem.SE launching, we should do our best to write detailed answers to the questions, rather than jump fast on the few existing questions, because these will later dictate much of the tone and quality of the site
Pchem II (thermo, stat mech) didn't have nearly as many fun integrals as I (quantum, kinetics)
I may have 'too quickly' starred @F'x 's comment
@Fx and and and vtc as much as needed! :D
Sooooo anyone here with any Python experience?
I'm using Python to code up my SCF procedure and I'm trying to figure out how to construct the Fock matrix
So @Aarthi are you our moderator until we have moderators?
6:48 PM
@LordStryker Well I will have some by the end of this summer... haha
italics*/*more italics doesn't work >:(
@LordStryker but that sounds like an SO question to me
or at least chat.SO
Yeah i fixed it
needed spaces @NickT
Whoever retagged, much better, thanks
@timothymh That won't help me! I've got less than two weeks to get this done. Hit me up in the summer if you need some help however! :P
6:49 PM
@Andrew I'm pretty much going to try to watch the tags as much as possible :P
Tags are a pet-peeve of mine on other sites I've been on (EE.SE/Gaming.SE) so I want to try to preempt stuff :P
okay, wrote my first answer, now going back to work
who renamed the room? it's cute.
@Aarthi our overlord, why?
just curious
7:13 PM
Just out of curiosity. We have any computational chemists in the house?
7:25 PM
@LordStryker yeah! hope I'm not alone, though
@LordStryker what's your field?
@LordStryker Python for what
I use it fairly often, but not for much heavy computational stuff, just for glue (e.g. scripting Gaussian)
I 'used' Gaussian but was fairly oblivious to it
Argh, is too long for a tag
I thought I put an edit in for… but it disappeared...
@Fx I'm in a lab that analyzes weak interactions for the most part
oh, the edit button is gone; someone else has one in the queue too
7:33 PM
We push computational accuracy to the limit here :P
Sorry I had to step away. A graduate down the hall was trying to characterize a very aromatic system with a 6-31G basis O.o
Weak nuclear force? Or just dispersion-type interactions?
Told him to throw a the very least some diffuse functions on the heavies in there and come back when it was done.
@NickT dispersion
pi---pi stacking
oh, that reminds me of a question
I'm close to submitting a paper that attempts to replace the benzene dimer as a standard pi-pi interaction model
@NickT I'm using Python to write up Hartree-Fock to solve small molecular systems.
@NickT At this point in time I've written the code to evaluate all necessary integrals (overlap, kinetic, potential and electron-repulsion). Now its a matter of just funneling this into a Self-Consistent Field procedure
@NickT that would be me :)
7:37 PM
rep for editing in private beta should be 100
@NickT Starred that!
@NickT it really should yeah
Me too
@Fabian I tried that one too, EAS was what I ended up using, but that's probably not great either
@Fx What type of comp chem do you do?
7:37 PM
Q: Reduce the reputation requirements for editing and approving edits during the very early beta

FabianThe current reputation requirement for editing posts or approving suggested edits are 500 reputation during private beta 1000 reputation during public beta Those are very steep hurdles during the very early stages of beta for a new site. On the new Biology site we had something like 2-3 user...

@LordStryker all :)
@Fx Any focus?
Car-Parrinello dynamics, forcefield-based Monte Carlo, you name it
@Fx high accuracy ab initio type stuff? :P
@Fx actually I wish this community existed about a year ago when I was trying to hash out MM type stuff on polymer chains. That project died.
@LordStryker from the plane-wave basis set BLYP to the high-prec localized basis set PBE0 stuff
I have access to HPC resources, that helps
7:39 PM
@Fx :D I manage our lab's cluster here.
It craps out more often then I care to admit but when its working its phenominal.
but right now, my CPMD wavefunction won't convergeā€¦
@Fx Its MD. You can't always expect it to work :P
@LordStryker it's not yet MD, because the wavefunction for the first force calculation won't converge
We pretty much stick to MP2, CCSD(T), F12 type stuff and a little DFT on the side
That recent question about carbocation reactions makes me wish we had a way to doodle resonance structures on this site.
7:41 PM
@LordStryker never did any post-HF stuff, I'm a classical guy who got his fingers into DFT, that's all :)
Had a freq job on an 8-atom system took 3 months to finish on a hex-core machine with plenty of RAM.
Research projects are slow here.
@Fx well I wish I knew the classical side a bit more.
7:56 PM
but that just left a gaping hole...I thought it was cleaner :\ /sigh
@NickT never happy, this one :)
Maybe it's when you use the thing that moves messages to other rooms
I no has the power
@Fx those too? Just dump them in the Sandbox?
8:12 PM
@NickT I commented on your post.…
13 messages deleted
Q: Does GFAJ-1 use Adenosine triarsenate as its energy currency?

PeteRegarding the bacteria found in Mono Lake, CA that scientists believe uses or can use arsenic in its DNA backbone where life as we know it uses phosphorus (according to their experiments depriving the microbes of phosphorus and providing much arsenic), have researchers conjectured and tested whet...

Q: When collecting cell lysates for a Western blot, how do I induce di-sulfide bonds?

leonardoI would like to conduct a simple dimerization experiment for some protein I'm collecting from a cultured cells. My thought is, that if I'm running a non-reducing, denaturing PAGE gel, then removing beta-mercaptoethanol/DTT from the sample buffer should be enough to allow di-sulfide bonds to form....

Q: Does a theory exist for the formation of thylakoid structure?

Richard TerrettI'm interested in how the structure of the thylakoid forms into its characteristic highly rugose stacks of grana. What causes the thylakoid to invaginate and self-associate, albeit with what appear to be fairly large gaps in between folds?

Q: How fast will cells lyse under hypotonic conditions?

gkadamRoutinely, lysis of cells with hypotonic solutions is carried out along with some physical (douncing) or enzymatic (lysozyme) method to break open the cells. If one were not to do any of these and just resuspend cells in water, how long would it take to lyse the cells? I was discussing with a lab...

Q: During famine, does the human body do anything to prioritize which organs receive nutrients?

Gabriel FairWhen food is scarce, the body slows its metabolism. Are there any other systems or processes that encourage prioritization of organs?

@NickT what's with the flood? if you continue misbehaving, I'll totally find another room owner :)
I don't think that amount of feeds is a good idea for a small chat room
@Fx I want to own a room! Can I be next in line??
@LordStryker by the power unwisely vested in me by SE, I italicize thou
@Fx no way! I feel so professional now!
Entry on LordStryker's resume: Owner of SE:Chemistry chat room.
@Fx All feeds do that initially
@NickT If you need I can write up an actual answer for your pi-pi interaction post.
Nick T has made a change to the feeds posted into this room
Nick T has made a change to the feeds posted into this room
Nick T has made a change to the feeds posted into this room
Nick T has made a change to the feeds posted into this room
8:20 PM
@LordStryker I am a most of what you wrote is way over my head :P
@NickT ahhh *cracks knuckles
just looking for more crap to throw into my discussion section
This is right up my alley :)
Anyone know what the syntax is for inserting LaTeX code?
I tried the ` character.
@LordStryker $
@LordStryker $
8:26 PM
Ah thanks. doh
@LordStryker ` is for code
Yeah I just remembered that.
Q: Do trees really get a large volume of their mass from the carbon in the air?

Elliot BonnevilleI remember hearing that trees and other plants actually obtain a large amount of their mass from the carbon floating in the air, not the ground beneath them. Does the makeup of air actually contain enough carbon to support this theory, and is a tree's surface area actually large enough to obtain ...

-> Biology.SE?
and "volume of mass"? :P
9:13 PM
@LordStryker Impressive/imposing :P
If you're in need of a collaborator :P
I'm treating this question as another question on my Pchem final...probably severe overkill for the guy who asked it, but what the hell
plus it gives me an excuse to refamiliarize myself with TeX
Well since we've just entered beta, we should all put our best foot forward when answering posts. I think we should all treat our answers as if it were going to be peer-reviewed. Bonus points for a scholarly citation.
just basic thermo
how do you make an arrow in tex...ffs
\rarr, no, \arrow, no, \rarrow, no...
9:17 PM
ignore the horrible formatting
@NickT If you need to know the code of a symbol in LaTeX, use this handy-dandy website.
@NickT You just draw in the symbol and the program returns a list of possible hits (complete with syntax)
I hang out in the LaTeX chat room a lot. They are a great group of people if you ever need a quick tip regarding LaTeX.
I've gotta run. I need to go pay an electric bill before they close.
can I get equations to line up on = in mathjax?
@NickT on the basics, do you agree with my answer?
I haven't said anything about why eutectics are lower, in fact, because I'm not so sure and I haven't got my books around
@Fx yeah, I was writing an answer more along the tack of freezing point depression (not sure if it's too far off topic)
I think the relevant assumption that's easy (or easiest?) to break is that the solid formed is pure
9:48 PM
@NickT well, I think it could be useful, and indirectly linked to the question, so I'd say go ahead!
I really hope we have some organic chemists around, because I'm sure that we will have a lot of synthesis questions
10:38 PM
Finally this is out of proposal.
10:55 PM
@Fx we meet again.
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