1
$\begingroup$

Can $\ce{CD4}$ or $\ce{CT4}$ be considered an alkane?

I know that an alkane is $\ce{C_nH_p}$ where $p = 2n + 2$. An alkane is considered a "hydro"carbon, i.e., a compound containing purely carbon and "hydrogen" only. However, "hydrogen" has mainly three isotopes: protium ($\ce{^1_1H}$ or $\ce{H}$), deuterium ($\ce{^2_1H}$ or $\ce{D}$) and tritium ($\ce{^3_1H}$ or $\ce{T}$).

Thus, in general, can $\ce{C_nH_xD_yT_z}$ be considered an alkane/ene/yne, where $x, y, z \in \{ 0, 1,\dots,2n + 2 / 2n /2n-2 \}$ and $x + y + z = 2n + 2 / 2n /2n-2$?

$\endgroup$
3
  • 1
    $\begingroup$ What is the meaning of $2/2n/2n$ ? $\endgroup$
    – Maurice
    Mar 29, 2023 at 8:34
  • $\begingroup$ @Maurice Correlate it with alkane/ene/yne : 2n+2/2n/2n-2. $\endgroup$
    – CHEMUMAN
    Mar 29, 2023 at 9:50
  • $\begingroup$ You are asking a question about CD4 before introducing D. This is bad. $\endgroup$ Mar 29, 2023 at 9:59

1 Answer 1

3
$\begingroup$

Yes, they are still alkanes and they are named deuterated/tritiated alkanes. It's correct that alkanes are primarily considered hydrocarbons but if the hydrogen is replaced with deuterium/tritium, the names are also changed and this replacement is not a theoretical one. Practically this is possible (ACS Catal. 2018, 8, 3, 2296–2312).

$\endgroup$
5
  • $\begingroup$ Can we call them D/T-substituted alkane? $\endgroup$
    – CHEMUMAN
    Mar 29, 2023 at 5:07
  • 3
    $\begingroup$ @CHEMUMAN Is $\ce{H2^{18}O}$ water? Yes, it is. $\ce{CD4}$ is nothing else but $\ce{C^{2}H4}$. Do not let convention $\ce{^{2}H}$ being written as $\ce{D}$ confuse you. H in CH4 means hydrogen, not protium. $\endgroup$
    – Poutnik
    Mar 29, 2023 at 10:57
  • $\begingroup$ @Poutnik What do you mean is that $\ce{CH_4}$ is actually a mixture of various compounds of isotopes of carbon & isotopes of hydrogen(e.g.: $\ce{^14_6C _1^3H_4}$ is also methane), isn't it? $\endgroup$
    – CHEMUMAN
    Mar 29, 2023 at 11:17
  • 6
    $\begingroup$ @CHEMUMAN Yes, I do. There is nowhere said methane is a compound of carbon-12 and hydrogen-1. Molecules differing just by isotopic composition are called Isotopologues // Hydrogen is exception just formally, having dedicated symbols for its isotopes, as they have relatively biggest differences due the biggest relative mass differences. So H, D, T as hydrogen-1, hydrogen-2 and hydrogen-3 formally look like 3 different elements, while being just one. $\endgroup$
    – Poutnik
    Mar 29, 2023 at 12:03
  • $\begingroup$ @Poutnik The link provided by you really helped. Thanks. $\endgroup$
    – CHEMUMAN
    Mar 29, 2023 at 13:27

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.