Kratochvilite Wrong Formula or wrong Syonym (Chemical Name)

Hello ,

there is an error on the Kratochvilite page. The formula of Kratochvilite is describeded as C13H10. This formula won't fit to the Syonym (in this case the 'chemical Name'. It named Anthracene here, but Anthracene has the formula C14H10. The correct name for C13H10 is Fluorene. This was described correctly here :

[www.handbookofmineralogy.org]

i know that the identification of Kratochvilite as Fluoren was questioned in the 1995 timeframe. Anthracene was discussed as possibility, but (as i know) no more data becomes available.


Best regards
Elmar

Well unless we know which is wrong (formula or identity with anthracene vs flouren) we can't really change it!

Hello Jolyon,

there is an 100% error. You have only this pairing possibilities :

Fluorene ----> C13H10

Anthracene -----> C14H10

But now its crossed (C13H10, Anthracene) this is chemically incorrect . This chemical Names are fixed to a defined formula. At first i would change the Syonym to Fluorene (like Handbook of Mineralogy). If this proved wrong (new data becomes available) the mineral must be redefined. I'am in contact with Uwe Kolitsch to solve this problem. I'am able to analyse a Typ specimen if i get one .

Best regards
Elmar

A Manual of New Mineral Names (1892-1978) (Embrey & Fuller) lists kratochvilite as C₁₃H₁₀, synthetic name fluorene, from the 14th List (1937)



Edited 3 time(s). Last edit at 11/12/2009 06:07AM by Rob Woodside.

"This chemical Names are fixed to a defined formula."

This is not true, especially not in organic chemistry where individual sum formulas refer to large numbers of different compounds. C14H10 can be anthracene, phenanthrene (benzo[ b]naphthalene and benzo[a]naphthalene, respectively) and a number of other compounds which are far less likely to occur naturally (e.g. tolane or p-ethinylbiphenyl, to name just two).

Confusion as to whether the mineral was fluorene, anthracene or phenanthrene stems from the techniques used for analysis. Elementary analyses of carbon and hydrogen are affected by a high measurement uncertainty. Even with today's modern equipment, relative errors are in the order of 3-5%. Therefore, a safe distinction between C13H10 (theory: 93.94% C) and C14H10 (theory: 94.34% C) is absolutely impossible.

A safe distinction between the three compounds requires 13C-NMR or 1H-NMR spectroscopy. If it is not just fluorene that needs to be confirmed or excluded, 13C-NMR should be preferred. When properly done, HPLC can also do the job, but some measures need to be taken in order to obtain safe results. Comparison of retention times is not sufficient here, although this somewhat depends on the impurities present in the respective sample. Minimum requirement for an unambiguous identification is the recording of UV spectra and comparison of them to those of certified reference materials recorded in the same solvent. Also, the individual compounds should be quantificated in order to make sure that the PAH are the main constituents of the sample and not just minor impurities in an unrelated material (this could also be accomplished with much less effort by a preliminary TLC run). This won't be obvious otherwise. I know that there has been at least one HPLC analysis tackling this problem, but the conditions were not reported. I would have to have a look at the chromatograms (sample, reference standards and blanks) to tell whether the results are reliable.

Note that none of the aforementioned techniques was available in 1937.



Edited 1 time(s). Last edit at 12/03/2009 07:52AM by Peter Haas.

Hello Peter,

i agree that my simplified description "This chemical Names are fixed to a defined formula" is somewhat misleading. What i mean is that "this chemical Names are fixed to a defined formula and STRUCTURE".

What i try to say is, that there is a discrepancy between the given chemical formula here on Mindat ( C13H10 ) and the given syonym (Anthracen).
You know better than most mineral collectors without background in organic chemistry : C13H10 can never be Anthracen. This is 100% wrong !!

Analysis: I don't agree with you.

3 weeks ago i've performed (with the help from our Analytical guru) some analysis of similar specimens (fumarole material from Anna dumps, Alsdorf).
We were not sure is it Ravatite (Phenanthren) or Kratochvillite (historically Fluorene in Handbook of mineralogy or maybe Anthracene ??).
We decide to use GC/MS wich performs very well in this case. There was absolutely no problem in differencing Phenanthren and Fluorene with the provided "Wiley275"-Database. The combined methods providing enough data to differencing the molecules (retension-time and molecular mass). If you have to differ Phenanthrene and Anthracene its not easy, but with proper calibrating (Anthracene follows the Phenanthrene shortly) you have a good chance (common practice in enviromental-analysis).
If i can get original Kratochvilite i'am able to clarify the composition easily.

Best regards
Elmar

No response a long time....................

Hello folks,
i'm somewhat frustated that this thread is getting lost in time. Don't let this error be ignored.

Best regards
Elmar

Elmar, we don't know which to change - the formula or the name? Yes, we understand that this is wrong, but without a definitive new study of kratochvillite, we would just be guessing which was wrong, the chemical name or the formula. I'll add an explanatory note, but won't make a change.

Hello Alfredo,
i'm understand that we have to wait on a new study about that. But i think we can decide to one of the pairs 'C13H10 Syonyme:Fluorene' ,wich is more reliable (see Handbook of Mineralogy). [www.handbookofmineralogy.org] or name it 'C14H10 Syonyme :Anthracene'. This is an correctable error, and i know : If you correct this, it wouldn't solve the lack of a new study, but is much more scientifically correct.

The situation at the moment is like :
You have a picture of a 'car' but the description (syonym) say 'motorcycle'. You know this is wrong . There are two possibilities : Change the picture to a 'motorcycle'-pic or change the description to 'car'. In the end both possibilities are better than to claim this car picture shows a motorcycle. It's not funny to look on the Car picture with the motorcycle description for the next years.

Best regards
Elmar



Edited 1 time(s). Last edit at 12/28/2009 10:58AM by Elmar Lackner.

Elmar, I added the name "fluorene", because it wasn't in the database yet, but I can't remove "anthracene" because, rightly or wrongly, it has appeared in literature as referring to kratochvillite, but there was already an explanation on both the kratochvillite and anthracene pages explaining the situation.

Incidentally, quite a lot of physical/structural properties are recorded for kratochvillite. Isn't it possible to definitively match these to either fluorene or anthracene, without new chemical analysis?

Hello Alfredo,

many thanks ! Looks better now.
Small typo : on the Fluorene Syonym page you have the Anthracene as C13H10. Must be C14H10.

And for the Anthracene page a more correct text is: Chemical name for a polycyclic aromatic hydrocarbon with the formula C14H10.
see : [en.wikipedia.org]

this is because in organic chemistry are other components with the same formula. See here the link for Phenanthrene / Ravatite):
[en.wikipedia.org]

And for analysis :
With modern methods we won't have a problem in identifying this.

Best regards
Elmar

Thanks, Elmar; corrections made, to the english versions anyway. I leave it to someone else to add comments to the french and german pages for Anthracene.

I have just uploaded a picture of the material/find that Elmar analysed
-> [www.mindat.org]
Cheers! Frank