The Periodic Table - 2016-05-28

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8:02 AM

@TIPS the hang of it

8:48 AM

!!greet/@Name.disp

Welcome to The Periodic Table @Name.disp! 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!

9:01 AM

0

Q: Optimization and DFT-D3 energy calculation in GamessFireFly version 8.1.1

My input was $CONTRL SCFTYP=RHF DFTTYP=B2PLYP DFTD=.T. d5=.T. RUNTYP=OPTIMIZE $END $DFTD VERSN=3 $END $SYSTEM TIMLIM=3000 MEMORY=30000000 $END $BASIS EXTFIL=.T. GBASIS=acc-pvdz $...

density-functional-theory

^ for comp chem dudes

9:13 AM

user image

@TIPS In Russian, the words for "square" (in a city) and "area" (geometry) are the same. There is a joke: "Hello, could you please tell me how do I find the Lenin Square? - It's simple: just multiply Lenin's height by Lenin's width".

All Russians are dads.

9:29 AM

user image

user image

LOL

user116211

Good afternoon comrades.

@CowperKettle How do I find the coastal area? - It's simple: just multiply coastal height by the coastal width.

1 hour later…

10:35 AM

how to check on what question i got downvote?

@DeNiSkA Go to your profile, reputation tab.

Or, if it's recent, just click the drop-down.

1 hour later…

11:51 AM

user image

12:17 PM

!!img/sodium tristearate

No result found.

!!img/triglyceride

user image

!!img/methanol

user image

12:18 PM

What side-product would their reaction produce?

@LeakyNun Do you want to make biodiesel?

Yes

Then your side-product is glycerol.

!!img/propane-1,2,3-triol

user image

I also intended to make glycerol

@Loong

1:14 PM

@TIPS i had 911 reputation but now i have 909, but i don't see any -2 in the dropdown or in reputation page on my profile

2 hours later…

2:48 PM

@DeNiSkA This might be because a question you edited got removed, or its author deleted.

1

Q: Transition Metals colours and electron absorbtion

I understand that when d-orbitals split some electrons can occupy the higher orbitals by absorbing frequencies of light, but do these electrons then fall back to their original ground states? If so, why? Why don't they remain in a permanently excited state?

transition-state-theory

3:04 PM

-5

Q: Self-pinging behaviour inconsistent

When I attempt to ping myself in chat (@KennyLau Testing), it does not work. Also, when I hover over my comment, it does not highlight my previous comment in grey as it would for others. However, if I try to reply to my message (:29967544 Testing), I receive the ping. In addition, when I hover o...

Wasn't this user in this chat before?

Yes

I know him

Whoa

Husband or wife?

neither

!!img/CH3[-]

user image

!!img/CH3^-

3:08 PM

No result found.

chemspider.com/Chemical-Structure.2299212.html

1 hour later…

4:29 PM

user image

3 hours later…

7:08 PM

What does it means to be isotropic?

9

Q: What is difference between homogeneous vs isotropic material?

When we say a material is isotropic? When properties such as density, Young's modulus etc. are same in all directions. If these properties are direction dependent, then we can say that the material is anisotropic. Now, when do we say a material is homogeneous? If I have steel with BCC crystal st...

terminology symmetry

thank you

Welcome

2 hours later…

9:11 PM

Hi

Hi @user1420303

tell me please

Re chemistry.stackexchange.com/questions/51911/… there are 2 things, I want to achieve.

1) I have to decide whether to typeset orbitals in italic or upright font. I am looking for a standard and authorative guidelines.

2) I need to create an algorithm to detect orbitals. I should not detect too much and not too less. I cannot, for instance look for "p" as physicists write "p" for proton. Therefore I was asking if my assumptions were correct.

1)

It seems I confused you by using the world "element", but I did not mean "chemical element", but rather "semantic entity of a chemical notation that someone might write using \ce"

9:17 PM

Well, as theoretical chemist, I would use upright font. IUPAC gives a lot of recommendations, but most of them is for non too technical things. In more advanced texts (papers) there is some flexibility. Some of the guys more recognized in the use of orbitals uses upright characters. I can suggest you some papers/book. BUT, I think that mhchem in this respect will be more useful for writing basic chemistry, so I would just stop in detect electron configuration: things like 1s22s2p6...

Because we really did not use this kind of thing outside the introductory chemistry courses.

2) "detect orbitals" from which kind of string?

I downloaded the chemistry.StackExchange postings and found 43k usages of \ce. There are quite some containing orbital notation like 1s^2 2s^2 2p^2 and I want to typeset it correctly. As I wrote in my question, I already did a literature research and found both ways, even in books of the same publisher. Sorry, if I don't consider your personal opinion as 'standard or authorative guideline' :-)

I should :-P

Ok, so you are trying to detect electronic configuration !

2) From all possible sensible inputs that someone might put into a \ce command. Someone = from any field of chemistry or physics.

People typed in 1s-H and 1s->2s and 1s->0 and 1s-2p

2p for a physicist could also mean "2 protons"

There also is sp^3-C which has to be rendered in another way than H-C or X^3-

Ok, Im thinking

chemwiki.ucdavis.edu/@api/deki/files/31162/…

Feeds meta.chemistry.se

0

Q: How good is the organophosphate tag?

I noticed a few questions appearing on the active tab that had the organophosphates tag. At first I didn’t think much, until I saw that it had been freshly created and is being applied to questions where it may fit. It also has a (short) tag wiki and a (bad, because it just copies the description...

discussion tags functional-groups

9:31 PM

Can we exclude some of the following notations? 2=any number, s = any of s, d, p, ..., X = any chemical element

s
2s
s^2
2s^2
s-X
2s-X
s^2-X
2s^2-X
sp
2sp
sp^2
2sp^3
sp-X
2sp-X
sp^2-X
2sp^3-X

for instance, nobody in 43k ever typed 2sp^3-X - but I am not a chemist and I need to know if that would be sensible input or not

no, it wont

you mean, you would't exclude any?

s
2s
s^2
2s^2 can be very common

I would exclude:

sp
2sp
sp^2
2sp^3
sp-X
2sp-X
sp^2-X
2sp^3-X

Why? I don't understand. sp^2 is very common. You just linked ot an image containing these.

Because where it would be written. One thing is to describe a list of orbitals in an electronic configuration: Like 1s^2 2s^2 2p^6 3s^2 ... That can be very used in general chemistry text.
But

even if sp, sp^2 and sp^3 can be mentioned many times, I found no add value to the \ce . If I want to say that "This carbon has sp$^3$ hybridation" , I gain no too much with \ce

2sp^3-X and 2sp-X doent have sense to me.

dont*

sp-X yes, but is it not the same that just type: sp-C ?

9:42 PM

It's not about what you would do. There are 450 usages here on SE. So people do use \ce that way and I want to support it.

Okay, things that do not make sense, that is what I am looking for.

There are people that type \ce{H} and I don't blame them.

Ok

Whether \ce{sp-C} renders the same as sp-C depends on the answer to my question 1)

@user1420303 I also cannot find any usages like 2sp^3-X and 2sp-X. So I can exclude it.

ugh?

Ah

I got it

(Used the "reply to this line" function, but it was not obvious.)

I would also like to get rid of s-X, as there are the abbreviations for organic structure fragments that are used in that way

Also here, I do not have any SE usage. But would it make sense to a chemist?

I got you. So I suspect that even if exist g, h, i ... orbitals, you can exclude them, they are not used except very specific situations.

No

@mhchem no

ouch

only sp-X, sp^2-X and sp^3-X, specially for X = C

it has not sence for X = H

9:52 PM

Let's finish the sp first.

I found 2sp, 2sp^3. I assume they make sense.

Show me the context please

I only know the question id. chemistry.stackexchange.com/questions/33279

or chemistry.stackexchange.com/questions/10207

chemistry.stackexchange.com/questions/13611

Ok, uhm, they are used with differents meanings

Sorry to be so ignorant: I don't really mind. I look at the letters and numbers and fonts and distances. But my chemical knowledge is almost non-existent any more.

It is really hard for me, because I am not aware of the number of the uses of each term.

9:59 PM

Yes.

I found 2sp, 2sp^3. I assume they make sense.

And of course I am ignorant about how people uses \ce, I would never imagine that people write \ce{H}

I did not find sp, but that fits nice.

I found sp^3-X.

I never found 2sp^3-X and 2sp-X

Look, Ill try to make it simple:

very simple)

s, p, d, ... are names that describes the shape of orbitals.
For atoms: each electron ocupy one orbital. If an atoms have many elements you describe it with something like:
1 s^2 2s^2 2p^3
( 1: means first energy level, s (shape s) 2 electrons ) (second leve, in shape s there are 2 electrons, second level in shape p there are 3 electrons...)

In a chemical bond, you use in principle one orbital from an atom, for example one p from second level (one 2p orbital) and one from other atom, for example other 2p.

In ONE atom, they can mix and you have mixes like sp, sp^2 (mixes one s and one s, or one s and two p)

so when you say:
sp-C you are speaking about an Carbon atom in which the mix gave sp orbitals.

if you say:
2 sp-C you are saying nothing

if you say "sp" you just say the mix of one s and one p
if you say "2sp" you can refer to TWO orbitals of kind sp, or the mix of one 2s and one 2p

That is all

Sorry by the extention

And please, add bracket notation!!

I learned something!

So, would someone say, for instance, s^2-C? Or does the one-letter orbitals always start with a number?

No, because every isolated atom has the orbitals s. Specify things like sp-C is important in the sence that this is not the natural orbitals that one would expect for the isolated Carbon. So we say that the Carbon is an sp carbon (a carbon atom in which its atomics orbitals mixed to form the sp).
If you say s-C or s^2-C you describe nothing of interest so no one would say that

I said sp-H has no sence because H orbitals can not mix in this way.

Normally only organic chemistries found useful to speak about these hybridized orbitals, and they normally work on C, so this kind of notation can be restricted to C, may including Si (silicon in english?)

10:15 PM

Well, maybe somone might use obvious, nothing-special notations to explain things to others. Like here on SE.

You might laugh, but I have sp^3-N in my list

(I love SE for having a download option so I could extract this list!)

(I soon have to leave.)

Well, as theoretical chemist sometimes is hard to work in collaboration with organic chemist, because we speak in different languages.
Look, the link I will past is the

review of one of the principal (2-4) chemist working (seriously) in this kind of things. You can inspect the notation.
http://onlinelibrary.wiley.com/doi/10.1002/wcms.1123/pdf
He also have a recognized book in the field.

I want to tank you for mhchem, it is very nice.

Thanks for your time.

Oh, two questions: What is 'bracket notation'?

What is the orbital list? spdghi ... Wikipedia seems not to have it.

Is a notation used to simplify a lot of thing, very extensively used in theoretical chemistry. It looks like:

cobalt.chem.ucalgary.ca/ziegler/educmat/chm386/rudiment/…

It is annoying to type it in latex, it can be done with $\langle A | H | B \rangle$

but when we have many many of them, it is disgusting to type

What is the orbital list? spdghi ?
Context please

brackets: < and > are still free in \ce.

| is also some membrane, but it could be typeset identically.

So you type some chemistry betwwen the < | and >?

Orbits can be represented by the letters s, p, d, ...

As you typed it, it is just a list of abreviations that receive the classes of orbital (grouped by shapes)

Notice that it is not exactly the symbols "<" and ">".

Most of the actual theoretical chemistry is wirtten in the bracket notation.

10:28 PM

... and where can I find a complete list of these abbreviations?

Brackets ?

Do you have a name or two of authors that use this bracket notation heavily? Or a word I could google to find usages?

List of abbreviations for orbitals: s, p, d, ...

(having two topics at the same time)

I called s, p, d... abreviations, sorry, they are just symbols

Every theoretical chemistry use intensively bracket notation. Mostly in papers. Or books, let me search example

Notación bra-ket

La notación bra-ket, también conocida como notación de Dirac, es la notación estándar para describir los estados cuánticos en la teoría de la mecánica cuántica. Puede también ser utilizada para denotar vectores abstractos y funcionales lineales en las matemáticas puras. Es así llamada porque el producto interior de dos estados es denotado por el "paréntesis angular" (angle bracket, en inglés), , consistiendo en una parte izquierda, , llamada el bra, y una parte derecha, , llamada el ket. La notación fue introducida en 1939 por Paul Dirac, aunque la notación tiene precursores en el uso del lingüista...

Okay, where can I find a complete list of the orbital symbols?

If not in iupac I do not know.

I only know s,p,d,f,g,h,i,j,k

10:33 PM

Brackets: But you do not put chemical formulae into the brackets. So it would not make so much sense to include it in \ce, because you need math features, not chemical-formula features.

They just represent: 0,1,2,3,.... The numbers go to infinity.

Brackets: Ok, I missundertood, I though \ce as a general chemistry purpose command.

Look, s,p,d, etc... are used in some context (as you can find in the periodic table or in wikipedia in the electronic configuration of the atoms), in such context, there is no more need than "f"

\ce became more and more general over time. But everything is along the lines of HCl(aq) + NaOH(aq) -> NaCl(aq) + H2O(l)

upload.wikimedia.org/math/4/1/a/… is a different kettle of fish

because the higher (h,i,j,...) are not "occupied". They are still important for theoretical treatments (look the tables of paper for example), but it is very restricted for ¿speciallist?

thank you so much

Your welcome

10:39 PM

good night

Good night

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May '1628

The Periodic Table

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