The Periodic Table

Jan

12:00 AM

@Loong Open source, blogs and Beyoncé? Do those topics even belong together?

Also, the following Youtube video must be cited if Beyoncé is mentioned:

J.B.O. Bejonze

►

@ortho nice edit! I approve.

Loong

@Jan I have no idea. Maybe all three are equally useful for our work.

Jan

Well Beyoncé certainly has a positive effect if the name reminds me of JBO, which in turn reminds me to turn on the metal music, so … Open source metal that is linked in blogs?

orthocresol

Apparently, that podcast includes "Joel's One Minute Tech Review of MRI machines", so it is relevant to us.

Jan

I had to Google MRI o.o'

Loong

> Disappointed that Joel will not discuss the divisive rant that he posted on SO a few weeks ago.

Jan

12:10 AM

Godwin’s Law, SE version:

> As the discussion grows longer, the probability of a rant on SE approaches 1.

Tesseract

12:39 AM

This conversation is definitely about chemistry. Very informative.

M.A.R.

6:59 AM

@Tesseract I wonder if that's sarcasm, or genuine delight

@SirCumference u still staring . . .

M.A.R.

7:25 AM

!!greet/@user123

Chemobot

Welcome to The Periodic Table @user123! 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!

M.A.R.

7:37 AM

Now I wonder how I can resize a Wikimedia SVG image.

Martin - マーチン

@M.A.R. change the pixel number in the link

M.A.R.

Oh, right!

Martin - マーチン

for example: commons.wikimedia.org/wiki/File:Dihydrogen-MO-Diagram.svg

M.A.R.

Also hullo

Martin - マーチン

https://upload.wikimedia.org/wikipedia/commons/thumb/a/a8/Dihydrogen-MO-Diagram‌.svg/_____ANY NUMBER HERE_____px-Dihydrogen-MO-Diagram.svg.png

o/

M.A.R.

7:49 AM

Hmm, should axes be upright or italic?

M.A.R.

8:15 AM

@Loong IUPAC's 2008 Green Book (iupac.org/fileadmin/user_upload/publications/e-resources/…) says axes as orbital subscripts should be slanted, while they're not variables. Why? O.O

Martin - マーチン

@M.A.R. they aren't variables?

M.A.R.

@Martin-マーチン I guess not

Aren't they axes?

Axes are labels, no?

Martin - マーチン

Are they?

I always thought of them as variables

because they essentially are a choice of coordinate system you are using

as such... x,y,z is convenient for 3D space.... but what happens when you are walking through 4D space?

M.A.R.

8:34 AM

@Martin-マーチン Maybe you're right

Martin - マーチン

@M.A.R. Maybe I'm wrong

M.A.R.

@Martin-マーチン I slip. It's slippery on the ground these days

@Martin-マーチン That chance is diminishing

Martin - マーチン

@M.A.R. Don't slip, always glide...

M.A.R.

The problem is Wikipedia isn't consistent with its choice among slanted and upright

Martin - マーチン

Well... it's Wikipedia.

Many of the science sites there are heavily influenced by a couple of pedantics...

when I see $log$ I die a little on the inside...

M.A.R.

8:37 AM

. . . which should've ensured that correct typography is applied

@Martin-マーチン Everyone is dying a little on the inside, every second.

Martin - マーチン

oh... typography always is a drama...

it's so much dependent on personal style and preference

M.A.R.

And strong opinions

Every notion that seems trivial but appears in scientific journals will have some pedants fighting for it

-- The Great M.A.R.

mhchem

10:08 AM

@LinearChristmas @Jan and others: I love the typographical discussion with you guys here. Very cool! The guys over at physics are a different kind of person. I saw a lot of minor typography issues and asked if they could need a little helper extension to ease input. ...

... Then I realized that they don't know the scientific typographic conventions and put it into a meta posting which got closed as off-topic. The difference between chemisty.SE and physics.SE couldn't be greater.

I am not supposed to put it into the comments. But here is my big thank you to all who joined the typography discussions!

Loong

11:17 AM

very related or dupe?

@mhchem Agreed. I have made similar observations on Physics SE.

in The h Bar, Nov 21 '16 at 18:46, by Slereah

Because who gives a damn about ISO standards

in The h Bar, Nov 21 '16 at 18:46, by Slereah

Especially for such matters as "the use of italics"

M.A.R.

I wonder how many people I would annoy if I say ''Because who gives a damn about ISO standards'' now

@Loong Who gives a damn about question marks?

Loong

11:36 AM

Yeah. It's not so easy.

If people ignore the rules for years and then are suddenly confronted with the rules, the correct rules are often met with opposition.

M.A.R.

@Loong BTW, did you get my ping?

Loong

@M.A.R. Yes. I am just looking into that book.

M.A.R.

Thanks ʕ ⊃･ ◡ ･ ʔ⊃︵┻━┻

Loong

Do you have a page number for that problem?

M.A.R.

@Loong Huh, I lost the page . . .

It was around 50 or something

@Loong IIRC it wasn't directly about the orbitals, but an axis subscript of something else

Prolly searching for 'angular' would work

Loong

12:04 PM

Anyway, I guess it's clear that the usual cartesian coordinates $x$, $y$, and $z$ are quantity symbols that must be written in italics.

The relevant rule for subscript is "A subscript that represents a physical quantity or a mathematical variable, such as a running number, is printed in italic (sloping) type."

For example, the $x$-component of $\boldsymbol F$ can be written as $F_x$.

orthocresol

The notation is for the subshells of electrons in atoms. The uses of x,y, and z correspond to the x,y and z axis in 3D space, and are therefore labels not variables. See: en.wikipedia.org/wiki/Atomic_orbital#Orbitals_table for the visualized shapes. — MaxW 6 hours ago

$\textit{p}_{+\textit{1}}$

M.A.R.

@orthocresol Yeah, that was the source of my confusion

orthocresol

Wikipedia is absolutely horrible on notation, though.

Loong

12:25 PM

@orthocresol Yeah, that comment is not helpful.

M.A.R.

The comment below it though, is the most helpful comment of the year.

Loong

yes

M.A.R.

I can't and won't deny how cool a person I am.

Also is it just me or is IUPAP much more ridiculous than IUPAC?

PvowelP reminds me of poop.

orthocresol

But chemistry is just applied physics, so technically we should listen to IUPAP.

M.A.R.

@orthocresol I'll do that when biologists start listening to chemists

Loong

12:34 PM

Should we clarify the subscript problem in our "italic or not italic" meta post? It might not be clear for all users.

When reading the comments, I am really surprised that some users think that the subscript $x$ in expressions such as $a_x$ should not be written in italics.

M.A.R.

@Loong Perhaps as a separate answer, which would include all the side comments

@Loong Which comments?

Loong

I would say this contradicts the basic rule of labels being upright (and I consider an axis name a label), but there we go. — mhchem 3 hours ago

The notation is for the subshells of electrons in atoms. The uses of x,y, and z correspond to the x,y and z axis in 3D space, and are therefore labels not variables. See: en.wikipedia.org/wiki/Atomic_orbital#Orbitals_table for the visualized shapes. — MaxW 6 hours ago

I wonder where this confusion is coming from.

Quantity symbols are always written in italics. There is no rule that says "quantity symbols used as labels are no longer written in italics".

Something completely different:

Can we remove the item that starts with "Aligned equations like" from the "italic or not italic" meta post? It has nothing to do with italic/roman type, and the post is already long enough.

orthocresol

+1

mhchem

You just quote the reason for the confusion: Is a "quantity symbol used as a label" a label or a quantity symbol?

Loong

12:59 PM

Hm, maybe the word "label" contributes to the confusion. The rules don't use it in this context.

And since "label" is not well defined, someone could consider all kinds of subscripts to be a label.

M.A.R.

@Loong Aye

Loong

Or maybe it's not clear that cartesian coordinates like $x$ are quantities and therefore $a_x$ is written with an italic subscript. There seems to be no problem to accept that heat capacity at constant pressure $C_p$ must be written with an italic subscript, since $p$ clearly represents a quantity.

mhchem

@Loong "The overall rule is that ... labels, are roman. Sometimes there may seem to be doubt as to whether a symbol represents a quantity or has some other meaning (such as a label): a good role is that quantities, or variables, may have a range of numerical values, but labels cannot." IUPAC

M.A.R.

@Loong Or both. They're not mutually exclusive

mhchem

What values can x in p_x have?

M.A.R.

1:07 PM

@mhchem When you plot y=3x, what value do you give to x?

My point being, a general good rule of thumb isn't always good.

mhchem

@M.A.R. I give it every number I can (and see fit my paper).

0, 1, 0.1, 1000, ...

Every number in that equation makes sense.

while p_x is just the same as p_south

M.A.R.

But is that the same train of thought when you see a picture of y=3x?

@mhchem Yeah, which should be slanted

mhchem

p_south?

M.A.R.

Yep, coordinates.

CowperKettle

> NASA will hold a news conference at 1 p.m. EST Wednesday, Feb. 22, to present new findings on planets that orbit stars other than our sun, known as exoplanets. The event will air live on NASA Television and the agency's website.

Details of these findings are embargoed by the journal Nature until 1 p.m.

nasa.gov/press-release/…

M.A.R.

1:10 PM

CowperNews update

mhchem

@M.A.R. Ha! If we cannot even agree if "south" is a label or a variable, we will never agree on p_x!

Loong

@mhchem Aha, that could explain better where this "label" problem is coming from. Thank you.

M.A.R.

@mhchem it's a label, but not a label label

o.O

mhchem

Can "south" have a range of numerical values?

M.A.R.

Not when you phrase the question that way. But how much south is important

Although I keep doubting whether I'll be right in the end of this discussion

But coordinates are slanted

Loong

1:16 PM

In that section, the IUPAC Green Book refers first to the official rules ("1. The general rules concerning …"). After that, the next part ("2. The overall rule is that …" reads like a rule of thumb.

M.A.R.

1 new question with activity; opens the question; is on-hold

Loong

And even IUPAC gives the example:
> The electric field strength $\boldsymbol E$ has components $E_x$, $E_y$, and $E_z$.

mhchem

@M.A.R. The IUPAC text I quotes gives an example with ...

@Loong Yes, I was just about to quote that!

M.A.R.

@mhchem Rule #178: For any relevant discussion, the chances of citing IUPAC sooner than Loong is infinitesimal.

2

mhchem

I still think that the x in $E_x$ is not a variable that can have multiple numerical values, but just a name for a direction, but there we go.

M.A.R.

1:23 PM

@Loong Which renders as slanted

Loong

@M.A.R. correct

orthocresol

@mhchem As I already mentioned in some comments, the $x$ in the $\mathrm{p}_x$ orbital is not a direction.

Not that it matters, anyway.

You have $\psi_{\mathrm{p}_x} = x\cdot f(r)$, $x$ can take any value from $-\infty$ to $+\infty$

mhchem

@orthocresol Yes, I read that comment. We were talking about "where does this confusion come from", here. My argument was, explaining how I initially interpreted p_x. The same way as E_x or something_south.

orthocresol

Ah, okay.

orthocresol

2:17 PM

@M.A.R. I didn't expect you to take me seriously.

Mithoron

Hello

orthocresol

@Mithoron $\require{unicode}\unicode{x1F44B}$

user123733

4:34 PM

@M.A.R. thank you

Hippalectryon

5:14 PM

:o chemobot is still running after all this time, what a miracle

Jan

Should he have died?

Hippalectryon

I was actually expecting that he would have crashed by now >.>

!!test

edited !

!!beer

5:22 PM

I’m thinking whether I should ask on the site what the term symbols of the f orbitals are, and how the corresponding orbitals look. But as I can’t really make it a self-answer, I’m not sure whether it would be well-received.

M.A.R.

5:45 PM

@orthocresol I never turn down a chance to surprise you

@Mithoron Jello

@M.A.R. o/

\o

o/

\o/

6:33 PM

Skull nations like deleting messages.

M.A.R.

6:50 PM

This is not for homework I am trying to figure out how to get sulfuric acid and MgSO4 is the only source I have found. — Jeff lee 46 secs ago

Same old, same old

Joe Stavitsky

9:41 PM

Could somebody point me at some practical applications of an iodine clock reaction (if there is such a thing?)

M.A.R.

@JoeStavitsky teaching kinetics

Joe Stavitsky

M.A.R. OK, I will just write pure theory lab then, fine=P

M.A.R.

!!wiki/iodine clock reaction

Chemobot

Iodine clock reaction

The iodine clock reaction is a classical chemical clock demonstration experiment to display chemical kinetics in action; it was discovered by Hans Heinrich Landolt in 1886. Two colourless solutions are mixed and at first there is no visible reaction. After a short time delay, the liquid suddenly turns to a shade of dark blue. The iodine clock reaction exists in several variations. In some variations, the solution will repeatedly cycle from colorless to blue and back to colorless, until the reagents are depleted. == Hydrogen peroxide variation == This reaction starts from a solution of hydrogen...

M.A.R.

Hmm, I din't think it's being used in industrial scale

hBy2Py

10:03 PM

@Loong, why are you composing a whitepaper in the Meta Chem.SE sandbox?

2

A: Formatting Sandbox II: please test stuff here

under construction Decision threshold and detection limit General aspects $$\textbf{Quantities and symbols}\\ \begin{array}{ll} \hline \text{Symbol}&\text{Name}\\ \hline y&\text{Estimate of the measurand}\\[-3pt] &\text{(e.g. measurement result of the measurand)}\\ u{\left(y\right)}&\text{Stan...

Loong

@hBy2Py It was a bit too long for a comment.

2

hBy2Py

10:25 PM

@Loong Mm. Tad.

Loong

@Gert If you are still interested, you can find two examples for the calculation of the decision threshold and the detection limit in this sandbox post on meta.chemistry.se. You can also see why the complete explanation for gamma spectroscopy would be too long for this format. — Loong Jan 1 at 16:58

orthocresol

@Loong I thought you were joking

Loong

And we don't have Documentation stackoverflow.com/documentation

Jan

10:48 PM

@orthocresol I starred it like a joke :D

Loong

Nobody takes me seriously.

Jan

Only sometimes I don’t.

Jan

11:09 PM

Why is it so hard for people to tag everyday-chemistry correctly? *curses quietly*

orthocresol

11:47 PM

@Jan I have to do chemistry homework every day -> everyday-chemistry

Loong

Then I wonder why we don't get any sunday-chemistry.

Jan

@orthocresol I use the sponge to wash up organic products → organic-chemistry

orthocresol

"I have a problem in organic chemistry." -> inorganic-chemistry

3

Jan

@Loong Because you need 300 rep to create tags.

@Jan Actually, rethinking this: My home work is washing up → homework

orthocresol

14

Q: Does benzene's resonance structure allow it to enter DNA?

According to this link, benzene is able to insert itself into the human DNA. It isn't an authoritative source and appears to be quite biased, so I'm wondering if there's any truth to this. The resonance hybrid structure of the benzene molecule causes it to have electrostatic potential, be ver...

The pseudoscience website linked in the question has disappeared.

I deem that a success :D

Loong

11:52 PM

I just want solutions for my problems.

2

Jan

@Jan Buying chemicals is inherently part of chemistry as well. I bet you have probably asked such questions at some point on a chemistry forum. And again, if you can direct me to a forum which answers this question then I will delete this question and don't just pluck some other chemistry forum out of the air. — 97980 2 mins ago

Where did this go? *sighs*

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