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5:22 AM
> Aluminium can form anionic aluminates, such behaviour being considered nonmetallic in character
Why is forming anionic aluminates a sign of non-metallicity?
 
 
2 hours later…
7:28 AM
@PhMgBr Turns out it is oxidized by water first. This turns it into Al(OH)3, and then, being an amphoteric hydroxide, it reacts with Na(OH) to form Na[Al(OH)4]
 
 
1 hour later…
NVZ
8:39 AM
5
Q: Are modern newspaper inks a health risk?

NVZIt's very common in India to see newspapers being used to absorb oils from oily snacks, or simply for temporary food packaging. Some articles say that covering food items in newspaper is a health risk. They also mention that using newspapers for these purposes are strictly disallowed. For example...

Is my question not fitted for the site? Is it about to get closed?
 
 
1 hour later…
10:02 AM
@PhMgBr Why did you kick @Chemobot?
 
10:25 AM
@Martin-マーチン \o
If it's about that other day that's the only instance of remembering kicking it, it was because it wrecked some havoc.
Still not sure about what happened, but it seemed there was a doubleflip with the wrong command and then it started posting 20 or so table flips.
 
I don't get it.
NH2?
O_o
 
!!doubleflip
 
Good afternoon, Muhammad
 
(ノ-_-)ノ ┫〝〟∵
 
That should be NH4+ and NH2-
In other words, a weak acid and a very strong base.
 
10:31 AM
NH2(-) is a very strong base, because it craves electrons. I see.
 
Also what the hell is NA+?
Sodium?
That's so wrong.
@CowperKettle The best thing to remember when gauging acid or base strength: The stability of the conjugate base/acid.
 
Ammonia is pretty stable, so NH2- is a pretty strong base.
 
Is there a conjugate base and a conjugate acid?
Or we can't say so in this case?
 
@CowperKettle These two are Lewis acids and bases.
 
10:34 AM
So in this case, there are no such things?
 
You only talk about conjugate acids and bases in the Bronsted-Lowry schema.
@CowperKettle Ja
i.e. the theory that says acids donate protons and bases accept protons.
 
Al(OH)3 is an acid, because it sweeps the environment from OH(-) ions?
Bases provide a lone pair.
 
@CowperKettle No, it's because it has an empty orbital that's being donated the electrons.
 
The Al that is.
@CowperKettle OYG
 
10:37 AM
Aluminium has a lot of empty orbitals.
It has the D shell open
 
Yup
 
Why not Al(OH)10 then?
 
How much space is available?
 
Ah. I see.
 
Al 3+ is a pretty small cation, so for meaningful bonds, we can only fit 4 OH's there.
@CowperKettle Also even if there were enough space, this wouldn't have happened.
There can be only up to 18 electrons in the configuration.
The 18-electron rule is a rule used primarily for predicting and rationalizing formulae for stable metal complexes, especially organometallic compounds. The rule is based on the fact that the valence shells of transition metals consist of nine valence orbitals (one s orbital, three p orbitals and five d orbitals), which collectively can accommodate 18 electrons as either bonding or nonbonding electron pairs. This means that, the combination of these nine atomic orbitals with ligand orbitals creates nine molecular orbitals that are either metal-ligand bonding or non-bonding. When a metal complex...
@Cowp I think a lot of info in the ^ page can be useful for you.
 
10:40 AM
nods
Again a simple problem in the textbook led me to open 20+ tabs in the browsers.
Of which I won't be able to finish even a half
 
(I mean, in the valence shell)
 
@PhMgBr 18e rule works best for organometallics, it's not so useful for typical coordination complexes, for example [Zn(NH3)6]2+ has 22 valence electrons
 
Too lazy to type
Snacks
 
Good afternoon, @orthocresol!
 
@orthocresol I was getting to it
Go on
 
10:42 AM
@CowperKettle for coordination compounds of main group elements, the most likely reason is simply sterics.
 
I'm typing with one finger
 
"simplesterics" was cool
 
@PhMgBr You remind me of a teacher i used to have who insisted on typing with two fingers only. We used to joke that if his computer crashed he would have to press ctrl and alt with his two fingers and then ask someone to come up and press delete for him.
 
!!flip/alt+ctrl+del
 
(╯°ਊ°)╯︵ɐꞁʇ+ɔʇɹꞁ+pǝꞁ
 
10:45 AM
So. Al(OH)3 is an acid here because..?
 
Back to 10 fingers again.
@CowperKettle Per the definition of a Lewis acid, because it accepts a lone pair of electrons.
@Cowp I used to mix this stuff up too and it made me really uneasy.
Couple o' things:
 
In a dative bond. Aluminium presents its empty orbital for the lone pair belonging to an OH ion?
 
@CowperKettle Yup
 
I hope that will remain in my brain somewhere.
 
These are different theories for different purposes.
You'd see Bronsted's definition a lot in organic chemistry, because it's straightforward, and Lewis's in coordination compounds, since it does an excellent job of explaining them.
@CowperKettle Don't bother yourself a lot with the theories themselves, but from now on, any acid-base reaction you faced, try thinking why stuff does what it does and which compound(s) are acid(s) and which are base(s).
 
10:51 AM
nods
 
If you stick to reading about the theories, you'd soon find yourself confused between different definitions.
"What was a Lewis acid? Was it the one that accepts electron pairs, or protons? Or maybe even it was donating electron pairs?"
 
How can OH- donate a lone pair if oxygen's electronegativity is twice that of aluminium's? Shouldn't it just draw all to itself?
 
the Al is no longer Al, but effectively Al(3+)
 
@CowperKettle What other electrons?
 
positively charged aluminium would like some electrons, so oxygen gives it some
 
10:54 AM
Al 3+ got no available electrons.
IOW, OH- and Al(OH)3 is much less stable than Al(OH)4.
 
Yes, but an electronegative element should not just "gift" electrons right and left
 
Also @Cowp, as @Ortho mentioned, electronegavities vary with adding or subtracting charges.
Al + is more electronegative than Al, for example.
 
But in Al(OH)3, the negative charge has been neutralized by three hydroxide groups
 
what do you think are the partial charges on Al and O in Al(OH)3?
 
@CowperKettle The negative what?
 
10:57 AM
is Al really neutral?
 
@PhMgBr the positive, sorry
 
@CowperKettle It is still a bunch of Al 3+ with 3 times more OH-'s around, innit
 
@orthocresol minus two on each oxygen, probably
 
@CowperKettle No no no no no no no no no, don't confuse oxidation state with charge.
Charge exists, OS doesn't.
OH has a real charge. Of 1-.
Al has a real charge. Of 3+.
 
What is then the charge on oxygen in hydroxide?
 
11:02 AM
@CowperKettle Less than a whole negative charge.
Coincidentally, in Aluminium cation the OS and charge are of the same value. Doesn't mean they're the same.
 
That is, from [-1;0]?
 
@CowperKettle The extra electron in the hydroxide system isn't just oxygen's.
 
How can I know what the charge of O in HO(-) is
 
You don't need to know.
People with strong computers and a pure heart and a German name and specialized software calculate this stuff.
 
> One Oxygen (OO) has a negative charge of -2. Think of it as 'wanting' to borrow two electrons, or it has -2 electrons... see, it is on the plus side.
Is this wrong?
This quote?
 
11:04 AM
@CowperKettle OO?
 
3
A: Why does the hydroxide ion have a negative charge?

riley3131Hydrogen exists as $\ce{H2}$, while oxygen exists as $\ce{O2}$. They are both diatomic elements, meaning that their stable form is a pair. There are several others... One Hydrogen ($\ce H$) has a positive charge +1. This has nothing to do with it having more protons than electrons, as it has ...

From this answer
 
Or are those binoculars
 
i gotta -1 that answer
 
@CowperKettle :o
It's a very idiotically simplistic view on the matter.
 
Is it a really bad answer?
 
11:05 AM
Yes, OH- is not O 2- + H +.
 
Okay, I'll downvote it too then.
 
That's . . . wow.
Let's ping @Mart to share some of this annoyance.
Both O and H are neutral species. Do not confuse charge with oxidation number. — Richard Terrett Dec 6 '12 at 7:52
Warning for reader: This is a too simplistic view on the matter to be useful. It doesn't take nitpick to know that thinking of $\ce{OH-}$ as $\ce{O^2-}$ and $\ce{H+}$ is flat out wrong. — PhMgBr 17 secs ago
 
@CowperKettle Going back to the original question, you can view the bonding in Al(OH)3 as being primarily ionic, that is to say, it is composed of Al(3+) and 3OH-. The idea is that that aluminium ion can fit one more OH- around itself, so why not?
If you put lots more OH- floating around, some of it is bound to be picked up by the Al3+.
 
I see. Right to Al, the bond becomes covalent, and period 3 hydroxides become acids, because that OH(-) is no longer detachable.
 
0
Q: Introducing a hydroxyl group to this compound

EllaIs it possible to selectively add one hydroxyl group to any of the ring positions of this compound? It needs to be available to go on to form an ester linkage with another compound containing an acid group. I don't want to alter the compound I just want to be able to create a linker.

Reopen?
Still no effort.
 
11:14 AM
@CowperKettle Al(OH)3 can still act as a base, if you add acid to it for example, it will mop up the H+. The OH- can still come off if you prod it.
 
but, for example, B(OH)3 is fully covalent and no amount of prodding will get the OH- to come off. so B(OH)3 is purely an acid.
 
That's why we put H in front!
 
@PhMgBr I see, well that is unfortunate...
 
H3BO3
 
11:16 AM
@PhMgBr let's just not do that... I am on holiday.
 
@Martin-マーチン Good thing is, it turned back to its lovely self after the kick.
 
@CowperKettle yeah. that's a slightly misleading representation of the structure though, since it is in fact B(OH)3. it acts as an acid by accepting another OH-, not by donating H+.
 
@Martin-マーチン No, I meant to ping you to be annoyed by how simplistic is the view on that answer.
 
So Boric Acid never protonates water?
Interesting.
Or, it protonates water by accepting OH- from it.
 
Yeah.
It's special
 
11:19 AM
There was no mention of it in the school texbook, at least yet.
 
@CowperKettle yes, it never protonates water directly and it never forms a H2BO3- ion. The other thing to just bear in mind is that there is no sharp distinction between ionic and covalent, it is a gentle gradient and along the way you will get weird behaviour like the amphotericity of Al(OH)3.
 
Nice.
 
@CowperKettle an exercise for you would be to consider why B(OH)3 is more covalent and Al(OH)3 is more ionic
 
That should be easy
Al has a larger radius, and attracts stuff less vigorously
 
@CowperKettle the radius of Al is not what you need - it is the radius of Al(3+)
@CowperKettle what you could write is that, the radius of a hypothetical B(3+) ion would be extremely small and therefore the B(3+) ion would be strongly polarising. Consequently the B-O bond is more covalent in nature than the Al-O bond.
 
11:25 AM
@orthocresol I've seen introductory textbooks link almost everything together.
 
being able to explain stuff properly is important
@PhMgBr well, it is true, the larger radius of Al translates into a larger radius of Al(3+) i guesss
still, i don't think it's right to use atomic radii to explain the bonding in a (largely) ionic compound
 
@orthocresol Maybe they link larger radius in the same group to more electronegativity?
 
Indeed I failed to take taht into account.
 
It's inaccurate though, because of the Lanthanide effect and the Al-Ga thingy.
 
@PhMgBr yeah i think in the end it's the same thing - but you have to link it
in fact there is a second factor that favours covalency in B(OH)3 @PhMgBr maybe you could find it.
 
11:29 AM
@orthocresol Lunch
 
as with all trends in chemistry there are exceptions and anomalies everywhere... enjoy your lunch haha
 
Back
 
> NaAlO2
Sterically, Al is able to accept 4 items in a complex ion
Why O2 then?
 
@CowperKettle Because it can give some dative bonds?
BTW @Ortho what's the other effect you mentioned?
Anything with lone pairs can theoretically be a Lewis base.
All Lewis bases are equal, but some are more equal than the others.
 
11:44 AM
@PhMgBr pi bonding, from oxygen lone pair into empty boron p orbital
 
Yyyyyyeah
Falls asleep
 
@CowperKettle for example why not Na3AlO3, you mean? it probably has to do with the solid state structure, don't worry about it too much
 
> Anhydrous sodium aluminate, NaAlO2, contains a three-dimensional framework of corner linked AlO4 tetrahedra.
So it does connect to 4 items after all.
 
@orthocresol Right, I think I got that BF3 question right in the Olympiad.
 
Chemistry if full of exceptions. Enjoy your lunch.
 
11:48 AM
@PhMgBr what was the question?
 
It was pretty long, but the answer was dependent on understanding that p orbitals in BF3 interact.
 
@CowperKettle simple NaCl has [NaCl6] octahedra, so the structures of solids can be very complex and difficult to predict at times. as i said, don't worry about it too much haha
 
YOU EXPECT ME TO REMEMBER SOMETHING FROM MORE THAN TWO DAYS AGO
 
Okay (0:
 
@PhMgBr haha, good job on catching it anyway
funfact: people say that the B-F bond in BF3 is the strongest single bond known, but it's not really a single bond, it's a 4/3-bond, so it's cheating
 
user116211
12:31 PM
!!greet/@Petrichorr
 
Welcome to The Periodic Table @Petrichorr! 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!
 
user116211
1:11 PM
@orthocresol: o/
 
1:38 PM
hello everyone o/
 
1:49 PM
Hi, Freddy!
 
2:18 PM
Who are the good authors of inorganic chem books?
I've one book by a J.D. Lee (1991)
 
@Loong Thank you!
 
@CowperKettle I have the same book :p
 
Nice! It seems okay.
 
nods
 
2:28 PM
I've been reading Russian school textbooks, but I wondered what I could read in English.
 
Is your JD Lee book also in english?
 
Yes.
 
I thought it was in russian
:p
 
Oh, I've got a lot of Russian books too.
Like the texbook by Rudzitis and Feldman
But the last will run out in 130 pages. (0:
 
@cowp Is chemistry your favorite subject or you study anything else too?
 
2:33 PM
@manshu Chemistry was my most hated subject in school.
 
same with me
 
Jan
2:45 PM
o/
@Loong One is only a true chemist if that book is on one's bedside table. Or under the pillow. Or is the pillow. In any case, it needs starring ;)
 
:-)
 
 
1 hour later…
3:52 PM
When I see @Loong smiling I can sleep well at night.
 
@Jan hmm, since you all have such high praise for it, i shall go and check it out tomorrow ;)
there is a grand total of one copy, only for reference, in the science library...
 
@orthocresol The German original is printed on Bible paper. ;-)
 
@Loong Papyrus?
 
Bible paper is a thin grade of paper used for printing books which have a large number of pages. Technically it is called lightweight offset paper and is a type of woodfree uncoated paper. This paper grade often contains cotton or linen fibres to increase its strength in spite of its thinness. It is used for making Bibles, encyclopedias and dictionaries; as well as some fiction books such as the ones published by the Bibliothèque de la Pléiade. The Norton Anthology of English Literature is also known for using Bible paper (an essayist from the New York Times referred to it as "wispy cigarette paper...
 
@CowperKettle It's great that you want to read, but I would caution you against reading things that are too advanced... know your limits and stick to them. Sorry to be a spoilsport.
 
4:01 PM
!!flip/spoilsport
 
(۶ૈ‡▼益▼)۶sdoᴉꞁsdoɹʇ
 
@Loong Amazon says it's 1924 pages, I guess they needed some really thin paper
 
4:14 PM
@orthocresol Okay. (0: I will fall back on some Keats or Rossetti in case of boredom
I don't get this calculation. I get the part where we divide by molar mass.
Thus we obtain the molar quantity of ammonia.
 
Is the problem in the first part? w/w and w/v can be confusing.
 
We know that the solution as a whole has the density 0.899 grams per liter, with ammonia constituting only part of that.
@pentavalentcarbon I don't understand why they multiply by 1000 mL
The second and the fourth term are a mystery.
 
The fourth term should say 1 L in the denominator. There are 1000 milliliters in 1 liter.
That's needed because concentration/molarity M has units mol/L.
 
But why use this factor?
By multiplying terms 1*3, we get the molar quantity per 100 gram solution
 
Yes, which isn't very useful.
It's much more common to work with molarity.
 
4:22 PM
I don't understand how this multiplication gives us the desired result.
 
When I do these kinds of problems, where you're multiplying all these fractions containing conversion factors and things...
 
We don't know how much solution we have, so what's the use to plug in the density (factor 2)..
 
...I always, after each multiplication, scratch out or cancel units that appear in the numerators or denominators...
to see what my current units are.
Knowing my current units, and the final units I need for my answer, really guide you in what conversion factors (with units) are necessary.
 
Yes, when I cancel out the num/denom units, I do get the desired mol/Liters
But why.
 
Because we can cancel/multiply/divide units as though they're numbers or constants.
Like in algebra.
 
4:27 PM
@CowperKettle if you want to read something I'd recommend a gen chem book. There are some suggestions here chemistry.stackexchange.com/a/37306/16683 although I personally can't give any recommendations (I never used those). In addition to those listed, there is also this book amazon.co.uk/Chemical-Structure-Reactivity-Integrated-Approach/… Do check them out. (You may or may not be able to find PDFs on the web...)
 
@orthocresol Thank you, Ortho!
 
4:41 PM
I calculated it, and the numbers fit.
I mean, calculated how many mL there are in 100 grams of the total solution. 111.234 mL
Then plugged that instead of 100 g in the denominator.
And in the numerator, 28/17.04 = the number of moles per 100 g.
Then multiplied by 1000
Voila. (0: The long, dumb way.
 
user116211
5:25 PM
@Jan applies to all subjects ;O
 
Jan
What, the HoWi?
 
Are carbon's p-orbitals empty in CO2? O_o
 
Jan
@CowperKettle I want a big red whiteboard-marker type pen to cross out that entire 'diagram' of your's. Sorry.
 
this question interested me, and I decided to investigate, and found this diagram
 
Jan
Yeah, ignore it. It is bad. It is far away from the truth.
@CowperKettle And make a mental note never to go to Illinois for chemistry.
 
5:32 PM
@Jan Ha ha.
 
Jan
(Or take the MO diagram, that actually looks like something.)
 
I haven't yet read about MO.
So the orbitals are not empty.
 
Jan
They're simply not there in the way you are thinking now ;)
 
Okay. (0:
 
Jan
There are two pi-type occupied orbitals, orthogonal to each other that spread along the entire O-C-O axis.
Yes, they were once made from carbon's and oxygen's p-orbitals in the respective direction, but you cannot really say that they belong to either.
 
5:36 PM
@CowperKettle 2sp2 what?
What a diagram
 
> Professor Patricia Shapley, University of Illinois, 2012
 
Jan
Take that one instead. Much better.
 
@CowperKettle Shrug professors can be wrong too.
 
@Jan Thanks, Jan!
 
Like how @Mart was wrong about Iran losing to Brazil in volleyball.
 
5:44 PM
@PhMgBr glass shaterring sound What? Professors aren't god. This is ridiculous. I thought that I could be a professor someday.
 
Jan
@PhMgBr But @Mart's not a professor, is he ;)
@manshu So you're saying you can't be a professor, because you're god?
 
@Jan duh..yeah..
 
Jan
I had hoped for the opposite, getting god-like status by becoming a professor =C
Anybody here use Gaussian and has immediate access to the academic hierarchy it sometimes appends to the end of a file? =D
 
That's the wrong way. Steps to become a Professor are:

1. Become god.

2. Apply for professor.
 
Jan
@manshu I knew I was doing it wrong. My life is ruined Y,...,Y Again! Y,…,Y
 
5:49 PM
@Jan Academic hierarchy?
 
@Jan Don't worry. You can apply for god by taking a form from UNO. Fill it. Age limit is 30 years.
 
Jan
@pentavalentcarbon The one just above ;)
 
The link you posted points to your question. Is is supposed to point somewhere else?
 
@pentavalentcarbon That's the web
interweb
 
Jan
Oh damn, yes. here O:-)
@PhMgBr Can you modify that link up there with your admin powers? ;)
 
5:54 PM
If not a lot of time has passed, you can edit it yourself.
 
Jan
@pentavalentcarbon But too much not a lot of time has passed =C
Does @Chemobot support !!chocolate ?
 
Jan
Goddamnit =C
 
@Jan It's really a bad day to live for me
 
At least it supports !!beer, which I'm about to go have...
 
5:55 PM
 
@manshu That's a rather extreme statement.
 
corrected
 
Jan
But !!wine is the better drink imho.
I'm going to !!whine about the missing !!wine !!flip
 
((|||||┝\(`д´)/┥|||||))
 
Now that's a good flip.
@manshu Still extreme :(
 
5:58 PM
Does one need to understand quantum mechanics in order to understand the MO theory?
 
@CowperKettle At the deepest level, yes. At a cursory level, very little.
 
@manshu Good song.
 
@pentavalentcarbon :)
 
@Jan Maybe inorganic chemists are meant to drink wine and theoretical chemists are meant to drink beer.
 
6:01 PM
JD Lee's explanation of MO theory starts with this
Basically this is Chinese to me. (0:
 
@CowperKettle Remember a few days ago I asked the same question?
 
@CowperKettle I would definitely stay away from this.
I would try and understand this (chat.stackexchange.com/transcript/message/29374531#29374531) first.
 
@manshu No.. about the MO theory?
 
relevent to your question
 
Jan
@pentavalentcarbon So what are us organic chemists supposed to drink?
 
6:04 PM
@pentavalentcarbon I found a formula for this in my RUssian texbook.
 
Apr 26 at 15:05, by manshu
"Wave function describes the probability of finding an electron somewhere in its matter wave." and two wave-functions can combine where their signs are different.
 
@Jan All the ones I know drink hard liquor straight from the bottle because they hate themselves.
2
 
start from this thread
Apr 26 at 15:08, by pentavalentcarbon
@manshu The square of the wavefunction, $\psi^2$, describes the probability, not $\psi$.
And that's all you need to know
 
@Jan The juxtaposition of metal with accordion is very...unusual.
I like it.
 
Jan
@Hippa !!vodka
 
6:26 PM
@Hippa I was thinking; shouldn't greet be available to certain people, not everyone?
When I greeted some new users the past few days, they made the bot welcome me, which doesn't make much sense.
Holy crap; I just earned pundit on meta.Chem.
\o/
 
Jan
@PhMgBr I think that was my fault, btway xD
 
@Jan Make more mistakes please
Also, meta Q of the day:
 
🎺🎺🎺 AND HIS NAME IS JOHN CENA 🎺🎺🎺
 
0
Q: 9000 views in 4 days, foul play suspected?

HDunnThis GPS vs NAVIC question received almost 9000 views in the 4 days since it was asked. On average, 4 day old questions have about 30 views, with other high view question gaining just over 100 views. This doesn't seem right. The user is from India, so it might have something to do with it. Wh...

@Chemobot Next time you do that, I'll call the police.
 
Jan
So @PhMgBr, does that make you @JohnCena?
 
6:35 PM
@Jan No, I didn't post the meta.Jizz question.
 
Jan
Oh that guy is @JohnCena! =D
 
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