Talk:Chemical formula

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Missing information[edit]

I'm missing mentioning of other (more advanced) ways of describing chemicals, such as IUPAC nomenclature, or visual representations, as for example File:Flutamide.gif (how do you actually call these diagrams?). --Abdull 17:06, 6 December 2005 (UTC)

Those are usually called "structure diagrams". Itub 23:55, 2 January 2006 (UTC)


Ax2[edit]

um.... i wanted to know how to a write a chemical formula for given elements correctly. i know about the ratio method but it doesnt work with non- metals and non - metals. — Preceding unsigned comment added by 69.199.61.67 (talk) 15:11, 6 January 2006 (UTC)

Question[edit]

What does a formula such as FeS2-x mean? Can this be included in the article?

See Non-stoichiometric compound. Yes, I think it should be mentioned in the article. Itub 16:07, 9 February 2006 (UTC)
Thanks ;)

chemical compounds[edit]

Do the groups of chemical equations Ch3OCH3, Ca3(PO4)2,CO2,H2CO3 contain entirely of organic compounds?

No. DMacks 16:06, 4 May 2006 (UTC)

chemical/molecular/empirical formula[edit]

The article on Empirical Formula equates "chemical formula" with "empirical formula," and distinguishes "molecular formula"

The article on Chemical Formula equates "chemical formula" with "molecular formula" and distinguishes "empirical formula"

(There is no separate article on "Molecular Formula")

So who is right?

naming elements in formulae?[edit]

how are chemical formulae read in english? for example, water is [eich 2 oh], and what about iron - [fe] or [aien]?

Iron is just iron. for example, FeO is just iron two oxide. (It has to do with chemical nomenclature, also.) 75.5.10.153 23:08, 16 September 2007 (UTC)minidude09

Mystery Symbol[edit]

in a number of chemicle composition formulas, I've encountered a symbol before the equation that looks like the infinity symbol with half of the second loop sliced off, or an 'o' and a 'c' pushed together. I am wondering what exactly this symbol means in reference to the equation. I've not encountered it anywhere else before.

e.g- Goethite: 'oc' - Fe+3O(OH)

Sounds like the "proportional to" sign (∝). Maybe it's used to indicate a non-exact formula representation (correct chemical formula, but actual allotrope or mineral form not completely represented), but I'm only hypothesizing here. DMacks 02:43, 3 January 2007 (UTC)

Order[edit]

In which order are elements in the chamical formula ordered? --Artman40 12:32, 9 January 2007 (UTC)

There are many different conventions. One of them is the Hill system, which is basically alphabetical and which is useful when you have a long list of compounds that you want to sort (for an index, for example). In other cases people sometimes sort by electronegativity (for example, in salts and other binary compounds; it is more common to see NaCl than ClNa), and in others people write the formula in a way that suggests the structure of the compound (especially for small organic molecules, such as CH3OH). Itub 16:44, 9 January 2007 (UTC)
I think that there should be a section about that in the article. --Artman40 17:49, 10 January 2007 (UTC)

Other forms I see on the net...[edit]

I am uncertain how to read these formulas...

Thanks, CarpD 23:58, 23 October 2007 (UTC)

Brackets are customary to enclose a grouping which has an overall charge, as [B12H12]2-. Parentheses are customary to enclose a grouping which occurs more than once in the formula, as Fe(NO3)2. Also parentheses can be nested inside brackets, as [Co(NH3)6]3+

And @ means that the As is trapped inside the Ni12As20 cage, but not chemically bound to it. This notation became popular with the discovery of fullerene cages, which can trap atoms to form La@C60 for example.

These points could be included in the article. Dirac66 00:50, 24 October 2007 (UTC)

Thanks for the information. That helped a lot. But yeah, I think that would most definitely be in the article. Or, in this article, Structural formula? Thanks, Marasama (talk) 06:38, 22 November 2007 (UTC)

using this article tyou should use this article because it is important on your lesson because its all about compound and thats all thank you —Preceding unsigned comment added by 180.194.1.228 (talk) 09:42, 27 September 2010 (UTC)

I have added both points to this article on 8 January 2008. Dirac66 (talk) 22:45, 13 January 2008 (UTC)

Homework help[edit]

determine some example of atoms in the followig formula nac1,

— Preceding unsigned comment added by 71.252.44.236 (talk)

This would be a question for Wikipedia:Reference desk/Science, but the Reference Desk wants students to do their own homework. -- Beland (talk) 16:17, 19 April 2008 (UTC)
As well, it's important to use capital and small (Unicode term) letters correctly. I surely hope the student made a few mistakes in transcribing the question, though. If exactly transcribed, there's cause for worry. (In particular, "mb" in computer technology signifies millibits, which don't exist in any ordinary discussion. However, "mHz", millihertz, is a legitimate unit of measurement for quite-low frequencies.) Substituting an "l" (small L) for a numeral '1' has not been necessary once typewriters became rare. (Woops, was logged in, but no more. User Nikevich, who uses DHCP.)

74.104.151.42 (talk) 11:51, 15 December 2011 (UTC)

R[edit]

Some articles like keytone and functional group follow the standard practice of using "R" (sometimes with subscripts) to represent arbitrary structures. This practice should be explained in this article including why "R" is the symbol chosen and what it stands for. (Radical (chemistry)?) I've added the same note to Talk:Structural formula. -- Beland (talk) 16:14, 19 April 2008 (UTC)

Berzelius' name[edit]

The name "Jöns" is not spelt with an "o", but with an "ö". The two letters are not equivalent in Swedish and have completely different pronunciations, hence the "Jons" is a misspelling of the name. The article on Jöns Jakob Berzelius spells the name correctly and I have pursuant to that corrected the spelling in this article. It should thus not be reverted back to "Jons" as was done previously. Fassitude (talk) 23:50, 15 June 2008 (UTC)

Your first edit was reverted by a vandal fighter using an automated tool. Your edit probably triggered this because it had no edit summary (plus you were editing anonymously). Something as simple as "linkfix" or "correct name" would have prevented this :-) Cacycle (talk) 00:29, 16 June 2008 (UTC)

What are numeric subscripts called?[edit]

I've been trying to learn the formal name for the numeric subscripts in chemical formulae, such as the "2" in "H2O". I had hopes that this article would have this information, but, no luck. It it possible that there simply is no formal name? I was thinking "valence coordination [number]", but that is most likely to be incorrect.Nikevich (talk) 01:41, 25 July 2010 (UTC)

Number of atoms?--Wickey-nl (talk) 08:42, 25 July 2010 (UTC)

Should we have a notice about unsubscripted numerals in formulae?[edit]

I find it quite distressing, now that subscripting and superscripting are so easy in any decent HTML editing environment, to see barbaric forms such as "CO2" and "H2O". (I have even seen "H20" -- H-twenty!) My hope is that this article could discourage such usage. When composing text in an ASCII environment, one might use such a form as "H_2O", which I have seen occasionally.

I suspect that in-line forms are a consequence of general public ignorance of chemistry, combined with a rather dismal typical level of real literacy (I don't mean ability to read and write at 6th grade level) among native English speakers. As an aside, a Boston tank truck that delivers liquefied CO2 is prominently marked "Co2" — "dicobalt"! Truck lettering is not particularly literate in the USA, at least in the Northeast. Regards,Nikevich (talk) 01:41, 25 July 2010 (UTC)

Further Explanation Needed[edit]

I put [further explanation needed] after the second paragraph of the ions section, since it only says that sometimes you use brackets, and nothing about what they do. I still have no clue what brackets do. Njaohnt (talk) 18:06, 3 November 2012 (UTC)

It's not explained in best way, but brackets are often used in ionic formulae to isolate and set off the ionic species, especially when they are complicated ones. The ligand (atom or group of atoms) inside the brackets has one or more charges, positive or negative, and will act like a single charged species. If the compound is melted, each thing inside the brackets can be expected to swim around independently as a charged polyatomic ion, with the atomic attachments (covalent or semicovalent coordination bonds) inside the brackets, all still in place, holding it together. The same when the compound is dissolved in a liquid, if it can be. Also, the things in brackets tell how the compound can be made, out of other salts.

A complication is that for simple polyatomic ions, they leave the brackets out, as they are understood. Thus, you could in theory write [NH3][NO3], but nobody ever does. However, for complicated ions, you see it's helpful to write ferric ferrocyanide as Fe4[Fe(CN)6]3, which tells you it can be made from potassium ferrocyanide and any ferric salt, rather than writing Fe7(CN)18, which doesn't help at all.SBHarris 02:13, 4 November 2012 (UTC)

Not all chemical formulas are molecular formulas[edit]

The lead now says that chemical formulas are also called molecular formulas. Wrong. Table salt is certainly not composed of NaCl molecules, but NaCl is its chemical formula. Sodium chloride has no molecules, and so it cannot have a molecular formula. Molecular formulas are one subtype of chemical formulas, and since most chemical compounds don't actually consist of "molecules" (the crust and mantle of planet, for example), that's a good thing. Minerals are usually written as ionic formulas if that is possible, and these are usually limited by the number of species it takes to write out the unit cell of the mineral. For example, look at the many ionic formulas in the silicate minerals. Some of these are network solids that are long polymers of silicon and oxygen, with cations going along. Others are not. But most of them can be written with ionic condensed formulas that tell us more than empirical formulas do. Finally, however, empirical formulas, homely as they are, are one type of legitimate chemical formulas (even though they are not molecular formulas, either). Empirical formulas say less about structure than molecular or ionic formulas do, but they are still chemical formulas.

The article does a fair job of discussing these subtypes of chemical formulas, but the lead doesn't do a good job of breaking them out and preparing us for what comes later. Also, the lede didn't note the difference between a chemical formula (which is a line of symbols, although it can be condensed to suggest some simple structure) and a full structural formula (which is a graphical object). So the lead needs some rewrite. If nobody objects, I'll take a shot at it, but am writing here to forestall cries of outrage at a big lead change. However, think about it. SBHarris 02:46, 4 November 2012 (UTC)