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For other talk page archives see User talk:Walkerma/Archives. Other close archives include:

Archive1Archive3Archive4Archive5Archive6Archive7Archive8Archive9Archive10

Discussion on first draft of table

Henry's remarks on the new table, with Wim's remarks in between, Martin's indented near end, are:

    • The separating lines between the properties have been removed. This way it is a little harder to see which numbers belong with which properties.
      • This is a consequence of the new colour scheme and the use of table styles. We should align the entries better, that is true. Perhaps we can make them float to the top of the cells. And if necessary we can even add the extra parameters to re-introduce lines somehow.
    • The boiling point of a compound depends on the pressure and to a lesser extent, so does the melting point sometimes. If the reference pressure is 1 atmosphere, then the boiling and melting points are called the normal boiling and melting points. Those are the ones usually listed in tables as the boiling points and melting points of a compound. My preference would be to call them the "normal boiling point" and "normal melting point", but if "normal" isn't specified, it's assumed they are normal.
      • I accept that the normality of boiling and melting points are implied. Short acceptable terms are more important than long most accurate term, imho.
    • For certain fundamental compounds, especially gases, solvents, and low boiling liquids, I think it would be a good idea to list critical temperature, critical pressure, triple point temperature and pressure. This is especially true of petrochemicals, on which distillation and high temperature reactions are run.
      • Agree. Good recommendation. For the Supplement page? Or for the main table?
    • The density of gases is highly dependent on temperature and pressure. Most gaseous compounds at STP obey the ideal gas law, so their gas density at STP can be calculated by dividing their molar mass by 22.4 liters/mole. At high pressures, the density of many gaseous compounds becomes a complicated function of temperature and pressure, which is impractical to list in a table. The densities of liquids and solids usually cannot be calculated from any simple law and are much less dependent on temperature and pressure, although there is temperature dependence and a reference temperature should be given. The reference pressure would usually be 1 atm. My idea would be to give liquid (and maybe solid) density for gases and specify the density is for the liquid (or solid) and give the reference temperature when such data is available. For liquids, a reference temperature should be provided with the density and if data for the corresponding solid is available, provide that along with a reference temperature. If density is available for solids, that should be provided along with a reference temperature and similar data for the corresponding liquid, if available.
      • Can we do 'normal' density in the main table, and details per-temperature density in the Supplement page?
        • Fine, let's do that. Such things as linear or volume coefficients of thermal or pressure expansion (or contraction) can be listed on the Supplement page, when available, along with the reference conditions. H Padleckas 22:08, 6 May 2005 (UTC)
    • I would like to see enthalpy, entropy, and Gibbs free energy of formation from the elements, if available. Reference temperature, pressure, and phase (if not obvious) should be specified (usually 25°C and 1 atm).
    • The heat capacity of gases is usually too simple or too complicated to calculate (dependent on temperature and possibly pressure) and list. The heat capacity of solids and liquids is more constant and could be listed with a reference T and P.
    • It would be nice to have latent heats of fusion and vaporization (at a standard pressure, typically 1 atm). However, I admit this item and the previous item (heat capacities) may not always be readily available and maybe emphasizing thermodynamics a bit.
      • The thermodynamics are indeed important properties but not that important. Due for the Supplement page, I think.
    • Crystal structure may not be important for some gases and petrochemicals. Some other properties may aslo not be important for certain compounds as well.
      • I like the solid material properties, albeit optional

For polymers, certain material properties become much more important. I've noticed a number of chemical element tables leaving a blank for "speed of sound". Is that really important?

      • Agree on it not being important

Maybe I see things from a chemical engineer's point of view and you see them from a chemist's view. Sorry if I ruined your day for you. H Padleckas 19:17, 6 May 2005 (UTC)

No, I'm delighted to hear feedback! I think all of those data are on the #Supplement page, so they don't baffle & scare off our average user. Advanced users such as yourself still have easy access to all the data. Wim suggests putting subheadings from there in the main table, I think that's a great idea. The lines disappeared before I worked on it, I personally prefer them in, but Wim says the new style without lines is a Wiki standard format. I don't have strong feelings. I should have put the link on units and conditions from the old table, I'm sorry I missed that. I'll try & fix it before too long, but I must go for now. Walkerma 19:58, 6 May 2005 (UTC)
I've seen the old style Table of Properties template. Thanks for showing it here. As far as I'm concerned now, you can delete it from this User:Talk page now, because the page has already reached a rather lengthy 41 kB. The Zinc Chloride problem we discussed on this page is already settled, so that section is now obsolete and can be archived or even deleted to reduce the size of this page slightly.
When I wrote the above remarks, I had not noticed there was a Supplement page with the thermodynamic and spectral data. Now that I have reviewed the Supplement page as well, I think it is a good idea. Things are pretty good the way they are now. I think it's good that the newer table is narrower (in addition to smaller) than the old table. I still like the idea of light lines in the Table template separating the cells. Maybe I'll "chat" with Wim about this. I have an additional minor suggestion for the Supplement page:
  • In the UV entry for spectral data, to change that to UV-visible (or UV-vis) or allow both UV and Visible spectra entries to be made there. Some compounds may have an extended series of conjugated double (or triple) bonds and/or aromatic rings causes the UV absorbances to extend from the UV into the visible region. Other inorganic or organometallic compounds or complexes may also be visibly colored.
H Padleckas 06:19, 7 May 2005 (UTC)

I like to see this from the WikiProject point of view: is the chembox achievable to get the WikiProject done with any version? Nothing personal in there, I'd think. Wim van Dorst 20:47, 2005 May 6 (UTC).

That's a great way to see it. Walkerma 18:05, 10 May 2005 (UTC)

Re: lines within the table
I have update the table code to use the new template for the standard style. It is used for the header blocks. And I added the extra code (per field :-< ) for the horizontal lines. Personally, I like the open blocks best. Please comment. Wim van Dorst 17:05, 2005 May 7 (UTC).

Discussion on second draft of table

I am now trying to pull all of the ideas together into one table and one supplement. I have started by reformatting it to make the table narrow again and putting the lines back in as they used to be. I think I prefer it with the lines. To judge from pages like toluene and the most recent Cacycle page Cytidine diphosphate, I suspect Cacycle prefers the lines too, though he/she has yet to comment. The grey lines seemed to widen the table for some reason, but I confess most of my editing of formats is like a drunken man stumbling around in the dark- so if there's a better way of doing the lines I'm interested, Wim. I also changed the reference from STP to SATP- it seems that all the major sources like the CRC Handbook all use 25 °C not 0 °C- Henry, do you have any thoughts on that? I apologise that the table has now jumped down the page, I'm not quite sure why.
I need to update the content of the table and the /supplement when I get time. Then I will put up a couple of examples for people to look at, I plan on doing phosphoric acid and toluene, two major compounds that need complete tables. If I get time I may do one or two others- perhaps calcium chloride and tyrosine to give a broader range. I am also looking at the German pages to glean any ideas from there. Walkerma 18:05, 10 May 2005 (UTC)
  • It is going really very nice. Keeping the lines, I introduced the new colour of the colour scheme (looking back now, after all it is only a simple edit to have both the colour scheme and lines.
  • Have you considered a time line on the formalizing of this as THE chembox? Wim van Dorst 20:20, 2005 May 11 (UTC).

I'm sorry I haven't responded quickly, but I've had some things to do. I've tried earlier to play around with the formatting code on these data tables a bit, but I haven't figured out exactly what's going on either. This seems similar, but not exactly like the HTML language code for table boxes I once read about. I tried a few things here and there, but I haven't been able to finish figuring out anything conclusive yet. The lines in the tables can surely be useful to ensure data matches up with its entries. If there is an objection to the presence separating lines from an aesthetic or appearance point of view, then a very light, hardly visible color can be used for the lines like "EEEEEE". H Padleckas 07:51, 12 May 2005 (UTC)

COLOR="#FFFFFF"
COLOR="#F7F7F7"
COLOR="#EEEEEE"
COLOR="#DDDDDD"
COLOR="#CCCCCC"
COLOR="#BBBBBB"
COLOR="#AAAAAA"
COLOR="#F8EABA", for table header background
COLOR="#C0C090", for table lines


But, Henry, the lines are already back into the proposed format. And indeed as you suggest at a friendly and mild colour (actually #C0C090, I added it to your colours table above) from the new formalized ClockWorkSoul CoffeeRoll colour scheme. Have a look below (right hand side!) to see the current layout. Wim van Dorst 10:00, 2005 May 12 (UTC).
I coded the table slightly differently, using the {{standard template style}}, simply for code optimizing. It doesn't change the look and feel. I did remove the imho superfluous 'Click link for page', though. Wim van Dorst 10:14, 2005 May 12 (UTC).
Regarding the "click here" problem for the supplement link, I am concerned that it is not clear that more data are available. The very fact that Henry didn't spot the supplement link confirms that- I think I wouldn't have discovered it myself if I hadn't created it myself. Often if you click on a link that says liquid data you find it explaining what a liquid is, rather than the actual data. This is true for much of our standard table. I have tried to make the link clearer by adding the word "page" to the link- so people don't think, "Why should I click that, I already know what a supplement is!" Is this clear enough? Is there a better way? Walkerma 15:32, 12 May 2005 (UTC)
  • I think it is clear enough now. Wim van Dorst 15:54, 2005 May 12 (UTC).
In the new table on the right side of the page, I see horizontal lines about 1 (or 2) px wide right under each of the subheaders in the color="#F8EABA" bands such as "Walkerma", General, Hazards, Properties, Structure, etc. Those are ok, but they are not really needed because the color itself separates those bands from the "#FFFFFF" (white) background. However, I do not see horizontal lines separating each entry inside the white background, such as Systematic name, Other names, Molecular formula, SMILES, Molar mass, Appearance, CAS number, etc. Those kinds of lines would be useful. Am I overlooking something?
I've taken a look at the data tables Cacycle has put in Toluene and Cytidine diphosphate. The Toluene table was made with a code that looked like the "traditional" HTML code for tables, which I am more familiar with. The Cytidine diphosphate table was made with the slightly different sort of code I have only seen in Wikimedia so far, which we are now trying to use for making the new tables. I'm still trying to figure out how the Cytidine diphosphate table was made. I'm trying to see if there is a fairly simple solution to this problem.
I understand that for a lot of chemical data, especially thermodynamic data, a reference temperature of 25°C and 1 atm (SATP) is used instead of 0°C and 1 atm (STP), which is used for calculations of molar volume of an ideal gas (22.4 l/mole at STP) and I don't really know what else. Therefore, it was a good idea to put such a note at the bottom of the table. I clarified it a bit in the newer table by adding the actual SATP temperature (25°C) and pressure (1 atm) to the note. If metric units are prefered, "1 atm" can be changed to "101.3 kPa". H Padleckas 16:43, 12 May 2005 (UTC)

Sorry to come back to the lines in the new chembox: Are they ok now with all browsers? I have read the above paragraph a bit late, so Henry could you please confirm? Please find a screenshot of how it looks in all standards following Firefox on my laptop. Wim van Dorst 20:14, 2005 May 14 (UTC).

Design of Chembox supplement page

This is a schematic of the kind of thing I have in mind. I don't have the skill to put it together in a pretty way in a realistic amount of time. Where I have a single column for each category of data, I would foresee this actually being two columns, but I don't know how to write that even in a simple table. I don't really mind how it is cleaned up, I just think that the current format for the supplement page(written by yours truly!) looks messy & amateurish. Walkerma 15:22, 12 May 2005 (UTC)

Hey, that version you just put up works nicely! That's how I originally planned it, but I couldn't get the code to work! Thanks! Walkerma 15:35, 12 May 2005 (UTC)

Supplement table
Structure & Properties Thermodynamic data Spectral data
Index of refraction Phase behaviour UV-Vis
Dielectric constant Triple point Lambda-max
Bond strength Critical point Extinction coefficient
data data data
more data more data more data
etc. etc. etc.

So, you agree not to do a three (or six) column wide table, but use the sectioning power of wikipedia itself, organizing things with three normal tables. Good, that settles it. That means that I don't need to point out that such a very wide table in large font would really become problematic.

Now, I do have have some recommendations for the Supplement page:

  • introduction text what this particular supplement page is for, how to use it, etc.
  • better closing text with respect to SATP (or STP, I don't mind)

Wim van Dorst 15:50, 2005 May 12 (UTC)

Take a look at the latest version on the bottom of the new table on this page.
H Padleckas 17:03, 12 May 2005 (UTC)
Yes, I like the both the wider text and the presenting the proper information, but it should be correct (100 kPa != 1 atm), and I think the term SATP should not be split. How do you like my rewording? Actually, I was writing this recommendation only about the Supplement page, where I think we should seriously give this reference a proper text paragraph. But I'm glad you gave it attention in the Chembox too. Wim van Dorst 17:44, 2005 May 12 (UTC).
According to the article Standard ambient temperature and pressure and what I learned at the university, 1 atm = 101.325 kPa, so I edited the SATP note at the bottom for a reference pressure of 101.3 kPa.
H Padleckas 19:06, 12 May 2005 (UTC)
According to that very same article, I understand that SATP is NOT at 1 atm and thus NOT at 101 kPa, but at the 100 kPa that I mentioned. I don't want to start a flamewar, and a no/yes/no/yes discussion, so I won't revert your edit of the table. But I would appreciate it if you would be so kind as to point out to me what I might be overlooking for the SATP. Wim van Dorst 21:10, 2005 May 12 (UTC).
You are correct. The article Standard ambient temperature and pressure does state the pressure as 100 kPa. I changed back the bottom of the table to state 100 kPa. I wish that was the end of that. However, I looked at the Wikipedia article Standard state. In there, it says that a material's standard state is at 1 atm (101.325 kPa) and 25°C and that the standard state is the reference state for the material's thermodynamic properties such as enthalpy, entropy, and Gibbs free energy. So I went to the external link "Standard-state enthalpies" given at the end of the Standard state article. In there, it also says that a material's standard state is at 1 atm (101.325 kPa) and that a material's thermodynamic properties are generally listed at the its standard state. So now, I'm not sure whether SATP is the best reference condition to use. I'm still looking at a number of external websites about standard state in chemistry. In the meantime, I guess we'll leave the reference condition as SATP at 100 kPa and 25°C until something else is indicated. H Padleckas 01:20, 13 May 2005 (UTC)
  • better text about disclaimer.

Gladly I leave these things now to you (I have to do other things for a while).

  • I think we should have an automatic title generator such as using {{PAGENAME}} but I can't find a good link to how to do that (yet). Wim van Dorst 15:50, 2005 May 12 (UTC).

A few changes I made to these tables:

  • At the bottom of each table, I put in a light orange ("#F8EABA" color) band with the SATP note and the disclaimer link, similar to the front page table.
  • Previously, the bottoms of subscripts such as "f", "solid", "liquid", or "gas" on the thermodynamic symbols were chopped off. Increasing cellpadding near the top of the page from 3 to 6 seems to fix this problem.
  • Near the top of each table code, I deleted the phrase border-collapse: collapse; . As a result, separating lines appeared between the entries. In order to minimize the thickness of the border going around the table, I changed border color from "#C0C090" to "#FFFFFF" in the 3 tables. Deleting the border-collapse: collapse; seemed to allow an increase in width in some of these tables, but on this Supplement page, it shouldn't matter.

Generally speaking, the latest front page data table created for the Toluene article looks good. The lines separating the entries are very light-colored, 1 px in width, and look pretty good. The solid, one-color border looks fine too. It seems though, like the table is little wider than the data requires. Also for clarity, it seems like it would be helpful to separate each of the solubility solvent entries with horizontal lines. If I start any chemical compound tables soon, I think i'll use that table as a template unless something better comes along. I might make a few improvements in wording in Toluene some day. H Padleckas 02:33, 13 May 2005 (UTC)

  • Glad to see that you did an actual Toluene page with the new chembox. And I agree that is really looks very good. Fortunately, it also pointed out a major flaw in the linking to the supplement page, which I now have adjusted. Each chemical XYZ with a full chembox should have its own page, named XYZ chemdata supplement, such as Toluene chemdata supplement, to which the new chembox automatically links. Having such an aptly named supplement page, my automatic titling problem has been solved as well. Glad to see this done. Note that I intentionally used the word Chemdata as that does give a better title word than Chembox on an wikipage. This will be more informative for all supplement pages coming in the future. Wim van Dorst 09:05, 2005 May 13 (UTC).
  • I did try to minimize the width of the toluene chembox, but apart from some minor table coding optimizations (use <br> instead of double whitespace) I didn't find the real cause of the over-wide table. There must be some spurious whitespace somewhere, I guess. I'll keep trying. Wim van Dorst 09:05, 2005 May 13 (UTC).
  • After this compliment, I'm sorry to say that I dislike your layout changes to the default chemdata supplement page. The borders and their colours are chunky, come out two-toned, and having three times exactly the same SATP reference is quite suboptimal. It may be an browser-dependent thing where your computer renders it differently from mine, but I strongly propose to retain the light new chembox table layout (standard style) as previously was there. And to put a good explanation about the SATP/STP and other reference verbally in its References section. In my humble opinion that gives a much more readable layout. Wim van Dorst 09:05, 2005 May 13 (UTC).
I understand your aesthetic objections to the thicker (chunky?) border around the table rectangle, the two-toned lines, and their more imposing color(s), and triplicate SATP and disclaimer reference. Accordingly, I have essentially reverted to the previous version of the table before my edits, but did keep the increased cellpadding at 6 (changed from the old 3) so that the thermodynamic subscript symbols were not chopped off at the bottom. As I see it now, the table rectangle border is one-toned, thin 1 px width lines, and the separating lines are thin 1 px lines which are one-toned with a very light color almost blending in with the background color, but do serve to distinguish the entries for the careful reader. I plan to change the Toluene chemdata supplement tables similarly when I get a chance. H Padleckas 18:45, 14 May 2005 (UTC)

Shall we by default include the still open end of the MSDS into this same chemdata supplement page, as a separate section? There is no procedure for MSDSs in Wikipedia yet, so this may be a nice stub procedure. And comment it as to be replaced with the proper external MSDS link when available? I've implemented it in the draft. Wim van Dorst 10:14, 2005 May 13 (UTC).

Wim, I noticed you did the right thing and changed the link from NMR spectroscopy to Nuclear magnetic resonance. When I wrote the table I deliberately put in the above link, because while writing it I found there is no proper page for NMR spectroscopy as yet- but clearly there should be! Strictly speaking nuclear magnetic resonance is a phenomenon in physics, whereas the technique we know and love is an analytical method. The two things are very distinct and both are important enough to warrant separate pages (some would say a whole Wikibook each!). The current page is a bizarre mishmash- there is a lot of appropriate material describing the physics phenomenon , its history and the mathematical equations to go with it. Interspersed with it is little tidbits of information about the spectroscopy. Then there is a highly description of COSY without any explanation of basic NMR spectroscopy as taught to one million college students (guess or exaggeration) each year. I plan to split the page pretty soon and write a brief intro to NMR spectroscopy. So please can you indulge me and put that link back as it was?
Regarding the MSDS, the old box includes this link to an MSDS wikipage, and I left it as it was, but I don't think people have bothered using that system much as yet. We have to decide- is Wikipedia going to maintain a set of MSDS pages, or should we just provide links to SIRI or Oxford University MSDS websites? I don't care too much, as long as no one expects me to work on maintaining the pages... Walkerma 22:26, 13 May 2005 (UTC)
  • NMR: I had surmised as much, but decided to do the correct thing, and replace the redirected link. When someone in the future actually makes this NMR Spectroscopy article, he should also take action to follow all pages that link to the original page and check which of the two pages they would better link to. I did the same for the hydrochloric acid and hydrogen chloride pages.
  • MSDS: You addition to the stub paragraph on the supplement page completely covers the current practice of not working with any MSDS scheme sofar: it provides a good link (you can add the other too) to good information without bothering about any schematic approach of MSDS information provision. Wim van Dorst 07:50, 2005 May 14 (UTC).

See it live

Live examples on toluene compliments of Martin, and I did hydrochloric acid. I Like it!!! Plans to give live next Monday still on, is it? Wim van Dorst 21:22, 2005 May 14 (UTC). (note: updated both to narrow format. Wim van Dorst 21:18, 2005 May 15 (UTC).)

Thanks for all of the "tweaking." Assuming that the table works OK on all browsers, I think the only remaining issues are:
  1. The main table is still a bit wider than it needs to be. I will go hunting for unwanted whitespace this evening (delete sections of table, see if it shrinks in width).
  2. The 100 vs 101.3 kPa is still an issue as far as I'm concerned- I'm not going to assume that our page on SATP is correct. I've noticed that nearly all the ref. books and tables refer to 25 C and exactly 1 atm, so if we fix it at 100 kPa we won't have much info available! I'd like to verify things one way or the other in books as well as websites before we put the table up.
  3. The supplement page- as far as I'm concerned we can still edit this for another day or two if need be, though I plan to put up our Monday version as a template. Walkerma 19:45, 15 May 2005 (UTC)
  • The width problem is more than just whitespace: I already tried out all variations with respect to title/section/whatever deletions, and that's not it. I suspect now a derived effect of the standard template style. Let me work on it a bit.
  • I agree that the 100/101 kPa is an issue. Henry suggested to research it. I'm quite practical to support a text of 'SATP (25C, 1 atm)' albeit that this might be contradictory to formal statements elsewhere until we have a reliable (outside) source stating whichever definition it really should be.
  • Agree: Supplement page is later: this is about the chembox.

Wim van Dorst 20:37, 2005 May 15 (UTC).

    • Width problem really solved. Wim van Dorst 20:57, 2005 May 15 (UTC).
Thanks again, Wim, for fixing that width problem. I should have time to dig for information on standard conditions tomorrow, so hopefully we can post the template as soon as the pressure issue is resolved. Walkerma 23:25, 15 May 2005 (UTC)
After speaking with our person who speaks physical chemistry, and checking in several books, we came to the conclusion that the "standard state" IS set aT "25 °C and 1 bar pressure". The term SATP is not widely used, but for thermodynamic properties the term standard state is always referenced. My trip to the library explained the reasons for confusion- the 1985 JANAF Thermochemical Tables state that "in all previous tables, the standard-state pressure was 1 atmosphere (101 325 Pa). For this publication, the standard-state pressure is changed to one bar (100 000 Pa)." Yet I found a later (1994) secondary publication, the Concise Encyclopedia of Chemistry (de Guyter) still referring to the older 101 325 Pa standard in their brief entry on standard state. The latest CRC Handbook of Chemistry and Physics unequivocally states that "The standard state pressure is 100 kPa (1 bar)." Their tables are now corrected to this pressure. Therefore I'm going to amend the wording to match this, and post the template. I think it's silly that they made this change, but then I never did really get physical chemistry! Walkerma 17:25, 16 May 2005 (UTC)
Thanks for looking into the standard state, standard pressure issue. Sorry, I've been pre-occupied last couple of days. H Padleckas 07:07, 19 May 2005 (UTC)
I changed our standard state article to say 100 kPa instead of 101.325 kPa.
This is a valid point- though of course if we are using it as a template, we don't want to propagate a false idea. The JANAF tables actually say that for all of the compounds in the CONDENSED PHASES (solid, liq) the change due to pressure is insignificant. It will only make a noticable difference to gases (densities etc.), and then by only about 1%. Walkerma 21:43, 16 May 2005 (UTC)
Along the same lines, I have changed the notice from 100.000 kPa to 100 kPa: the latter is sufficiently accurate to indicate which standard has been chosen. Objectors are invited to calculate the difference in atmospheric pressure between the floor and the ceiling of the room in which they are sitting :) Physchim62 22:41, 18 May 2005 (UTC)

Draft version of Chembox table

Walkerma/Archive2
Walkerma/Archive2
General
Systematic name ?
Other names ?
Molecular formula ?
SMILES ?
Molar mass ?.?? g/mol
Appearance ?
CAS number [?-?-?]
Properties
Density and phase ? g/cm3, ?
Solubility in water ? g/100 ml (? °C)
Melting point ? °C (? K)
Boiling point ? °C (? K)
Acid dissociation
constant
pKa
?
Base dissociation
constant
pKb
?
Chiral rotation [α]D ? °
Viscosity ? cP at ? °C
Structure
Molecular shape ?
Coordination geometry ?
Crystal structure ?
Dipole moment ? D
Hazards
MSDS External MSDS
Main Hazards ?
Flash point ? °C
R/S statement R: ? S: ?
RTECS number ?
Supplementary data page
Structure & properties n, εr, etc.
Thermodynamic data Phase behaviour
Solid, liquid, gas
Spectral data UV, IR, NMR, MS
Chemical data NIST WebBook
Related compounds
Other anions ?
Other cations ?
Related ? ?
Related compounds ?
Except where noted otherwise, data are given for
materials in their standard state (at 25°C, 100 kPa)
Infobox disclaimer and references


See this

wikipedia talk:Chemical infobox Grrrrr! Wim van Dorst 20:59, 2005 May 17 (UTC).