The Periodic Table

@MAFIA36790 - shubh prabhat!

user116211

ha!

4:54 AM

Central Molecular Zone

The Central Molecular Zone or CMZ is a region of the Milky Way Galaxy rich in molecular gas. It is found near the centre of the Milky Way, and as such is in the Sagittarius constellation, between galactic longitude 1.7° and -0.7°, and latitudes -0.2° and +0.2°. It contains the Galactic Center Radio Arc various supernova remnants and emission nebulae. Regions with concentrations of gas are titled Sgr D HII, Sgr D SNR, SNR 0.9+0.1, Sgr B1, Sgr B2, SNR 0.3+0.0, Sgr A, SNR 359.1-00.5, SNR 359.0-00.9, Sgr C, Sgr E and also threadlike features called the Mouse, Snake, and Cane. Molecules found in the...

A good name for a chemistry chatroom

5:31 AM

This is a bullshit formula, isn't it?

Wikipedia says methyl acetate will reform back into methanol and acetic acid under the influence of NaOH.

Martin - マーチン

5:43 AM

@Mithoron I don't really know. I have a gut feeling about immiscibility being a bad tag, but I was unable to pin it down. I suggest you open a meta post about it to get a few more opinions. I would in any case rather use miscibility instead.

@ToddMinehardt @A.K. Please reject edits like this. The edit destroyed the question that was in there. Especially when they go into the reopen review queue.

user116211

7:48 AM

!!greet/@Wendylly

Welcome to The Periodic Table @Wendylly! 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!

8:14 AM

!!namaste/@Wendylly

user116211

@CowperKettle hehehe...

humari galti (0:

that was another phrase I recalled, meaning "my guilt" or "our guilt"

I also remember 'paani' and 'kitaab'

water and book

garam = hot

I don't recall 'cold' though

user116211

@CowperKettle I wouldn't help.... self-help is the best help.

D'oh

BBL, need to translate some

How is "bye" in Hindi?

!!flip/Namaste

(づಥਊಥ)づ︵uɐɯɐsʇǝ

user116211

8:21 AM

@CowperKettle o/

Wendy lly

8:54 AM

thanks for the greetings everyone

Q: What is known about liquid carbon?

9:39 AM

17

The wiki tells me that if you heat carbon at atmospheric pressure it eventually turns directly into a gas without being liquid first. At what pressure can you make liquid carbon? Has anyone actually ever studied liquid carbon? Surprisingly a web search did not answer these questions.

Freddy

10:48 AM

Li-Fi, 100X Faster Than Wi-Fi! | ColdFusion

►

12:54 PM

@MAFIA36790 Thanks for pointing this out, actually -- I probably never would have looked back at that question otherwise.

user116211

@Brian: o/

user116211

How do you guys use representation theory in Chem?

1:09 PM

@MAFIA36790 Only way I know of offhand is point/space groups in symmetry analysis.

!!wiki/point group

Point group

In geometry, a point group is a group of geometric symmetries (isometries) that keep at least one point fixed. Point groups can exist in a Euclidean space with any dimension, and every point group in dimension d is a subgroup of the orthogonal group O(d). Point groups can be realized as sets of orthogonal matrices M that transform point x into point y: y = Mx where the origin is the fixed point. Point-group elements can either be rotations (determinant of M = 1) or else reflections, or improper rotations (determinant of M = −1). Discrete point groups in more than one dimension come in infinite...

!!wiki/molecular symmetry

Molecular symmetry

Molecular symmetry in chemistry describes the symmetry present in molecules and the classification of molecules according to their symmetry. Molecular symmetry is a fundamental concept in chemistry, as it can predict or explain many of a molecule's chemical properties, such as its dipole moment and its allowed spectroscopic transitions (based on selection rules such as the Laporte rule). Many university level textbooks on physical chemistry, quantum chemistry, and inorganic chemistry devote a chapter to symmetry. While various frameworks for the study of molecular symmetry exist, group theory is...

user116211

@Brian yeh, yeh...there are group theory, ring theory and field theory in abstract algebra....

To my knowledge it's only groups.

But I don't know abstract algebra

user116211

1:11 PM

@Brian yep.

user116211

@Brian Chemists don't have to.

user116211

It's essential in advanced graduate QM courses and of course QFT.

For physicists?

user116211

@Brian: Thanks for the reply :)

I guess - maybe there are people doing heavy-duty quantum methods development who work with it?

user116211

1:13 PM

@Brian quite so.

user116211

!!greet/@LESANG

Welcome to The Periodic Table @LESANG! 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!

LE SANG

Hello! Thanks!

@LESANG Welcome to one of the analog SE's ;-)

LE SANG

I start to learn Chemical, just join here to have a look. Thanks!

user116211

1:20 PM

@LESANG We have an excellent community... just ask when you have trouble....

Q: define alkali metals and alkaline earth metals

Calling @PhMgBr, your aneurysm is waiting!

0

Define the following terms: Alkali metals Alkaline Earth Metals. I know that elements like lithium, sodium etc and beryllium, magnesium, etc are alkali and alkaline earth metals respectively. But whats their standard definition?

elements

user116211

But do show sufficient research efforts and ask conceptual query ;P

user116211

@Brian His exams are approaching; so he would not come for two weeks(?) or so.

LE SANG

Thanks! I still google to understand, I will ask if really stuck :)

@MAFIA36790 Ah, <shrug>, he'll still see it.

Advantage of the durable chat archive

user116211

1:23 PM

@Brian ohh.... ;D

@Brian He should ask this on Socratic

Q: Why do electrons not fully fill up all the orbitals sequentially?

1:46 PM

0

Why do electrons not fully fill up all the orbitals sequentially? By this I mean: why don't the electrons fully take up the previous orbit first and then move onto the next orbit? Take calcium for example, it's electron config is 2, 8, 8, 2. Why isn't it 2, 8, 10? Why does another orbit need to b...

quantum-mechanics electrons atomic-physics

> (I know that this is a chemistry question in a physics forum, but I really could not find a chemistry or even a broader science type forum here )

:-(

user116211

@Loong WTH!!

user116211

SE IS NOT FORUM ;((

user116211

!!flip/forum

( つ•̀ω•́)つɟoɹnɯ

2:54 PM

> Water chloride content: <50 ppm

May we possibly specify it thus?

"Parts per million"?

I've just come across this in an industrial checklist procedure document I'm translating.

3:11 PM

@CowperKettle Yep, that's correct

it's usually in mg/L units for aqueous solutes

But it can be ambiguous (mg/kg, umol/mol, etc.)

We consider each indifidual ion a 'particle'? Interesting. Thanks!

according to SI and ISO, ambiguous ~~units~~ abbreviations such as ppm are deprecated; however, they are widely used

I see.

3:28 PM

@Loong Heh, yeah, like % v/v. <shudder>

yes, such things are explicitly mentioned in the ISO standard

3:48 PM

[If you liked, please vote 1+ / [^] / ↑ Sign] (chemistry.stackexchange.com/a/51098/7951)

+ comments :-D

Todd Minehardt

4:41 PM

@Martin-マーチン - will do, thanks for pinging me on that

5:53 PM

o/

Freddy

6:33 PM

\0/

7:34 PM

How can I selectively hydrolyse a compound with both an ester and an ether ? I want to turn the ether into al alcohol while leaving the ester untouched, and I'm not sure what protection/deprotection I should use

8:59 PM

Why is there an ester tag but not an ether tag ?

9:49 PM

@pentavalentcarbon o/ I need help on a retrosynthesis exercise, do you have a moment ? :D

@orthocresol Or maybe you do ? :D o/ (also thanks for the comments)

you can tell me about it, i will be afk for a while (need to shower it's getting late)

I'm stuck on how to do this:

PhyCS

yo

does chalcedony react with

PhyCS

carbonic acid

Chalcedony is SiO2 btw

10:01 PM

I've tried a few thing, but it leads me to something that's a bit different, and I use a step I can't really explain

PhyCS

SiO2 + HCO3 --> this yields a product right

@orthocresol Basically I start with a diels-alder of the two last reagants

Then I'd try to do this, but I don't know how

Which finally leads me to

It's a lot like the target molecule, but I can't find a way to actually get the target molecule from there

DeNiSkA

why ina is not active for 5 days?

@DeNiSkA Doesn't he have exams or something ?

DeNiSkA

i don't know

10:07 PM

@orthocresol Also, I've tried searching for the target molecule a bit everywhere on the internet but I haven't found a single reference to it :(

@Hippalectryon these are methoxymethyl acetal (MOM) protecting groups. Perhaps look for "MOM deprotection".

selectivity wise the Diels-Alder doesn't look great to me, but I guess that is your way to make the 6-membered ring

@orthocresol Yeah. I just need to find a way to make the product, it doesn't need to be with a great yield

also what Loong said ^

@Loong thanks

10:16 PM

different ethers are slightly different, so there are some conditions that work well for these particular ethers

Well, that leaves the problem of the group on the right being on the wrong carbon and having one extra carbon atom :(

that feels a bit like a typo to me

@orthocresol But the double bond is also on the other side. Surely I'm missing something

yeah, as in it feels like a typo in the question

@Loong According to synarchive.com/protecting-group/Alcohol_Methoxymethyl_acetal, the deprotection uses compounds like HX, wouldn't those also react with the OMe ?

10:18 PM

the TMSBr in DCM looks promising

@orthocresol Do you mean the extra carbon, the group's position, the double bond's position, or several of those ? I'm confused.

as in, the extra carbon is kind of difficult to add in

You mean to remove ? There's an extra carbon in the reagants

so i'm not sure whether the question meant the final product to have an extra carbon

sorry, yes, i meant remove, and one less carbon

Oh ok. Even supposing there's no extra carbon, any idea how to get the rightmost group on the right carbon and the double bond in th right place ?

10:21 PM

what do you mean?

@Hippalectryon probably not at room temperature

@orthocresol The product I get and the target products are not the same

(on top: expected, bottom: what I have. Leaving the extra carbon aside, a double bond and the group of the right's placement do not match)

not sure

it leads me to think that there is a different approach for the ring formation

although i can't really see it

Hm ok :(

@Loong I'm off it's getting very late here. Sorry for badgering you like this :P but please do ping me if by any chance you find a solution to the problem above