The Periodic Table

2:12 PM

@MAFIA36790 Waitwotwhy?

> The correlation coefficient determined for the curve of the reference sample vs. test solution is not less than 0.95. (Can there be a "correlation coefficient" of a curve, I wonder.)

orthocresol

@Jan You have a candidate score of 39.

@CowperKettle Perhaps this: en.wikipedia.org/wiki/Coefficient_of_determination

CowperKettle

@orthocresol The phrase is from the System Suitability Test for an ELISA system.. I understand too little in statistics..

Jan

@orthocresol And what can I buy from that score? xD

orthocresol

@Jan Unlimited power.

52 mins ago, by Rubisco

Here's how mod powers will feel like after some days

Jan

2:22 PM

@orthocresol Muahahahahhaaaa~ >=D

Jan

2:35 PM

Maybe I should run.

*slaps myself* Bad @Jan; don't start thinking that! D=

DHMO

2:47 PM

when sugar reacts with sulfuric acid, carbon is produced

my question is: which allotrope of carbon?

Jan

@DHMO The black man’s #%$& allotrope of carbon e.e

DHMO

@Jan ???

Jan

Actually, something rather close to graphite. Diamond is only the preferred allotrope at very high pressures.

DHMO

what is "something rather close to graphite"?

Jan

Not an ideal graphite. Quite a few defects in the graphite structure, as in sp³-carbons, non-perfect hexagons etc.

DHMO

2:51 PM

... never mind

Jan

o.o Did you not get it or are you giving up?

DHMO

i don't get it

0

Q: Qualitative analysis question

My sir once while teaching qualitative analysis told us that there's a salt in laboratory which if inhaled, causes cold and cough. Is that true? Because today I was indentifying a salt in the lab which was alcl3 and now I can feel that I've cold and cough. Is it true? Any connection?

experimental-chemistry

wtf is this

Jan

Well, graphite is practically an ideal crystal, if you wish. A 2-dimensional infinitely-sized macromolecule. You can only call something graphite if it actually consists of layers of very large hexagon-tiled layers stacked above each other. Just like you can only say diamond if most of the structure consists of the ideal tetrahedral polycycle.

DHMO

@Jan so it's a new allotrope

Jan

But most of the time that 'carbon' is generated, it is too rapid a reaction for carbon to assume either of those idealised structures. That's especially the case for suger/sulphuric acid where you can watch the carbon structure grow. In that case, there is no way that pure graphite is generated.

DHMO

3:00 PM

I see

by the way, do you have any idea how to generate 15 resonance structures of H2?

Jan

What instead will be formed is something that mostly resembles the graphite structure but with a much larger number of defects, i.e. atoms that do not conform to the ideal graphite structure.

DHMO

I think I get it

so just amorphous solid

Jan

You could call it a new allotrope, but since it's unordered, one wouldn't.

Wildcat

a pile of crap will be formed, most likely :D

Jan

Well, depending on the size of the sample etc, you will get a cylindric rising 'pile of crap', hence the rude name I used for the reaction before ;)

I can do ten if I spin-label the electrons.

Wildcat

3:03 PM

allotropes
Different structural modifications of an element.

DHMO

@Jan how?

Wildcat

Well, in accordance with the IUPAC definition, it is a new allotrope. XD

DHMO

also, I'm thinking maybe what if 2s is involved

Wildcat

There are no any restrictions on an ideality of the structure.

Jan

The normal sigma bond, H+ H-, H- H+, H. H. singlet, H. H. triplet and each of those with reversed spin.

@Wildcat But graphite is defined as an idealised-strucutre allotrope =O

Wildcat

3:06 PM

@Jan sure

DHMO

@Jan what does singlet and triplet actually mean?

Jan

Singlet: S = 1. Triplet: S = 3.

DHMO

now what is S?

Jan

The total spin quantum number.

DHMO

isn't it half-integer?

Jan

3:07 PM

(please don't bite me if that was wrong @Wildnicecat)

Wildcat

Everything is right. :)

@DHMO the keyword is total

DHMO

@Wildcat ??

Wildcat

it is the spin of all the electrons, not of a single electron

DHMO

How is this triplet?

Wildcat

Count with me.

First, note that you don't need to consider paired electrons

since in each and every pairs electrons are with antiparallel spin

pentavalentcarbon

3:09 PM

@Jan That should say singlet: $2S+1 = 1$ and triplet: $2S+1 = 3$.

DHMO

@pentavalentcarbon thanks, understand now

Wildcat

so they cancel spins of each other

or, right

multiplicity is 2S + 1

now

DHMO

@Wildcat I'm intrigued, please continue your explanation notwithstanding

Wildcat

you have 2 unpaired electrons

DHMO

just ignore the conversation between me and pentavalent

Wildcat

3:10 PM

each with s=1/2

total spin is thus 2 * 1/2 = 1

multiplicity is then 2S + 1 = 2*1 + 1 = 3

it is a triplet

DHMO

alright

Jan

@pentavalentcarbon Thanks; it has been a while since I did that kind of thing … ^^'

DHMO

why 2S+1 in particular?

Jan

Because quantum mechanics.

> To err is human, 2 R + 1 is quantum mechanics.

2

pentavalentcarbon

@Jan I would judge you harshly but it is very easy to mix them up. Teaching it to undergrads can be super confusing too.

Wildcat

3:12 PM

Cause each and every state with total spin S is (2S+1)-fold degenerate (in the absence of magnetic field).

DHMO

@Wildcat ????

Wildcat

They differ by M_S values.

Well, you need to learn a lot to understand how to deal with the total spin of a many-electrons system...

:D

orthocresol

sighs

DHMO

is the total spin 1 or 3?

Wildcat

depending on a system and its state

for your system S=1

there are, however, 3 states corresponding to S=1

that's why it is called a triplet state

DHMO

3:15 PM

I see

orthocresol

@Wildcat I think the multiplicity arose from some spectroscopy usage, did it? Never bothered to look into it

Like under magnetic field some lines were split into 3 lines --> triplet

Wildcat

@orthocresol yes, I kind of mentioned that

each and every state with total spin S is (2S+1)-fold degenerate (in the absence of magnetic field).

DHMO

is there quintlet etc?

Wildcat

I just did not finish, that in magnetic field the degeneracy is removed.

@DHMO i think it is called quintet

DHMO

@Wildcat is there quintet etc?

Wildcat

3:18 PM

and then you can have sextet, septet, octet, nonet, etc.

certainly

DHMO

is there?

Wildcat

you could have as many unpaired electrons as you wish

for example?

quintet: Mn(H2O)6^3+

:o

3:20 PM

take any molecule with at least 4 electrons and consider a state in which 4 electrons are unpaired

S = 4 * 1/2 = 2

2S + 1 = 2*2 + 1 = 5

that is it

it is a quintet state

DHMO

I see

Wildcat

However, if the question was is there any molecule for which the ground state is a quintet one...

DHMO

You know, transition metals lol

Wildcat

pubs.rsc.org/en/Content/ArticleLanding/1987/C3/…

Heh, even without TMs.

:D

DHMO

lol

What does "non-kekule" mean?

pentavalentcarbon

3:23 PM

Wildcat

Non-Kekulé molecule

A non-Kekulé molecule is a conjugated hydrocarbon that cannot be assigned a classical Kekulé structure. Since non-Kekulé molecules have two or more formal radical centers, their spin-spin interactions can cause electrical conductivity or ferromagnetism (molecule-based magnets), and applications to functional materials are expected. However, as these molecules are quite reactive and most of them are easily decomposed or polymerized at room temperature, strategies for stabilization are needed for their practical use. Synthesis and observation of these reactive molecules are generally accomplished...

DHMO

@Wildcat I like the first one

it doesn't have an aromatic ring

Wildcat

@DHMO You, you don't like aromatic rings?! :O

pentavalentcarbon

!!greet/Heath

Wildcat

You're not a chemist!!!111 :D

DHMO

3:26 PM

@Wildcat ...

Chemobot

Welcome to The Periodic Table Heath! Here are our chat guidelines and it's recommended that you read them. If you want to turn Mathjax on, follow the instructions in this answer. Happy chatting!

Wildcat

test $1$

CowperKettle

> Aliquoted 2 ml glass ampoules containing 5 mg/0.2 ml, dispensed under sterile conditions from 4 ml vials containing 100 mg of bevacizumab.

Is this verb "aliquoted" common usage?

Does it mean "we took a 2 ml aliquote"?

pentavalentcarbon

yes

CowperKettle

Does "We aliquoted 70 mcl into a sterile microtube" mean simply "we collected a 70 mcl sample and transferred it into a sterile microtube"?

Aliquot is just a fancy word for "sample"?

orthocresol

3:32 PM

@CowperKettle yeah pretty much

CowperKettle

Thanks!

Jan

Aliquot is biologistic for sample, imho.

CowperKettle

nods

DHMO

0

Q: will mercury vaporize in boiling water in a flask?

Will mercury vaporize with the water vapours if boiled in a flask full of water ? and if we store mercury under water in the beaker will it still give vapours ?? Thanks

inorganic-chemistry

Every liquid vaporizes... right

CowperKettle

> To err is human, 2 R + 1 is quantum mechanics, R2 is statistics.

DHMO

3:46 PM

does oxygen increase water's conductivity?

orthocresol

4:00 PM

Not that I know of. I don't see why it should, being uncharged.

Jan

4:16 PM

I might need to bounty somebody or something again soon o.o''''

Anyways, I'm off o/

orthocresol

5:07 PM

@Wildcat I realised that right after I posted that...

._.

Not thinking very straight. GS is negative linear combination.

Which means, it is time to sleep!

user116211

@orthocresol o/

orthocresol

sighs

Wildcat

@orthocresol I made a mistake in my comment as well.

These orbital are spin orbitals.

They are always different.

By definition.

:)

orthocresol

Ah, no wonder..

Wildcat

In the ground state $\psi_a = \phi \alpha$ and $\psi_b = \phi \beta$.

orthocresol

5:11 PM

I am thinking in spatial orbitals, that's why.

Wildcat

Where $\phi$ is the doubly-occupied spatial orbital.

orthocresol

And spatial wavefn in GS is symmetric.

Got distracted by other stuff IRL and ended up not writing my ochem answer :(

Tomorrow, I suppose!

Goodnight all `(.•.)´

Loong

6:17 PM

1

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