I'm studying organic chemistry, and I noticed that there are fluoro-, chloro-, bromo-, and iodoalkanes. However, there are none for Astatine. Could someone shed some light on this, and what it would be called?
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8$\begingroup$ Astatine is so unstable that for most chemical purposes you may just as well consider it non-existent. $\endgroup$– Ivan NeretinCommented May 28, 2017 at 15:05
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10$\begingroup$ The fact that you're unlikely to come across an organoastatine compound doesn't make the question unimportant or uninteresting; astatine derivatives have definitely been made, and there are certainly naming conventions. $\endgroup$– JSKCommented May 28, 2017 at 15:37
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$\begingroup$ There also should more be carbon-hydrogen astatine compounds like for example methyl astatide (CH3At) , dimethyl astatide (CH2At2) and so on. But it is highly radioactive like all astatine compounds,so it might just break down into its elements $\endgroup$– Bruh MomentsCommented Apr 29, 2021 at 2:26
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2 Answers
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Part of the reason why there has been very little research done on organoastatine chemistry is the extreme radioactivity of astatine; the half-life of $\ce{^210At}$, the longest-lived isotope, is about 8 hours. However, the element can be incorporated into organic compounds (e.g., via a destannylation reaction).1
In organic chemistry, the prefix is "astato-", as in astatobenzene or 3-astatotamoxifen, both of which have been synthesized.1,2 This is analogous to "fluoro-", "chloro-", and so on. As a general term, astatine compounds can be referred to as astatides (e.g. aryl astatides, analogous to aryl fluorides, chlorides, etc.).1
The aforementioned synthesis of 3-astatotamoxifen is shown below.
As for inorganic nomenclature, astatine can be denoted with the prefix "astatido-"; this follows from the IUPAC Red Book for nomenclature of inorganic compounds.
Milius, R. A., W. H. McLaughlin, R. M. Lambrecht, A. P. Wolf, J. J. Carroll, S. J. Adelstein, and W. D. Bloomer. Appl. Radiat. Isot. 1986, 37 (8), 799-802.
Samson, G., and A. H. W. Aten. Radiochimica Acta 1970, 13 (4), 220-221.
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There's a page for it on Wikipedia. Have a go at reading it.
https://en.wikipedia.org/wiki/Hydrogen_astatide
There's something interesting here. With Astatine being so electropositive, dissociation of $\ce{HAt}$ could form $\ce{H-}$ and $\ce{At+}$. If you tried to add this to propene, you would most probably get 1-astatopropane rather than 2-astatopropane.
Don't push your luck too far. Before you can call your fellow chemistry buddy and say "Hey look here! This is 1-astatopropane!" It's gone. That's because Astatine is highly radioactive:
$$\ce{^{210}_{85}At -> ^{206}_{83}Bi + ^{4}_{2}He}$$
With a half life of 8.1 hours, your beloved 1-astatopropane is going to decay away, leaving only a trail of alpha particles, and a few gamma photons. sob
Actually, for that matter even $\ce{HAt}$ isn't going to be there for long.
answered May 28, 2017 at 15:24
Pritt says Reinstate MonicaPritt says Reinstate Monica
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2$\begingroup$ The logical follow-up question: what happens to the 1-astatopropane molecule once its astatine has become bismuth? Could you conceivably use this to wedge bismuth atoms into molecules where they wouldn't normally go? $\endgroup$– zwolCommented May 28, 2017 at 22:05
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7$\begingroup$ @zwol A nuclear decay releases so much energy compared to a chemical bond that chemistry can be ignored when considering nuclear decay. In practice you'll probably end up with ionized bismuth, hydrogen and helium after decay. $\endgroup$– ntoskrnlCommented May 29, 2017 at 0:45
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$\begingroup$ @ntoskrnl Not really chemistry.stackexchange.com/questions/65809/… $\endgroup$– MithoronCommented Oct 4, 2020 at 20:09