enter image description here

Example from the Recommendations 2013. Left: Alleged disilazane ; Right: My version

enter image description here

Clearer example without obvious flaws in alternative structure. Left: Alleged disilazane ; Right: My version

I am confused with the contemporary IUPAC nomenclature of organic compounds. According to Recommendations 93 (available at acdlabs.com), silazanes are heterogeneous hydrides where both terminal atoms are silicon atoms (R- The same can be concluded from the general rule on heterogeneous hydrides (R- However, in the introductory chapter of Recommendations 2013 (which is freely available at RSC Publishing site) on page 82 the compound given in the image is given two names, with the least priority (non-PIN) variant being 1,1′-(2-ethenyl-1,2,3-trimethyldisilazane-1,3-diyl)bis(ethan-1-one). I am confused by this name, as, by rule R-, terminal atoms should be lowest in the Hantzsch–Widman order, which preserves unambiguity of the structure. From this rule, I expect disilazane to be something like the structure on the second image (although I acknowledge that the tetravalent nitrogen must be positively charged, which changes the name automatically).

TL;DR So the question is:

Do Recommendations 2013 change something about naming heterogeneous hydrides? And if so, what is now called silazanes?

  • $\begingroup$ With view on both the wikipedia entry (en.wikipedia.org/wiki/Silazane) and by a commercial supplier (sigmaaldrich.com/chemistry/…) I would like to hint that the second formula features a tetravalent N the aforementioned examples (and the first example by you) do not. I thought «disila» then indicates the presence of «two atoms of silicon» as in the right hand example and HMDS (en.wikipedia.org/wiki/Bis(trimethylsilyl)amine) though. $\endgroup$
    – Buttonwood
    Apr 7, 2020 at 16:34
  • $\begingroup$ I know about the tetravalent N, I addressed it in the question. I will add another pair of structures for my point to be clearer; it is just that this is example from the Nomenclature book. $\endgroup$ Apr 7, 2020 at 16:42
  • 2
    $\begingroup$ The Recommendations 2013 are not bug-free, in fact: see, for example, the 2nd structure on page 75. $\endgroup$ Apr 7, 2020 at 16:50

1 Answer 1


It seems this name should not be in the blue book. It is an error.

The following instruction is what Corrections to Nomenclature of Organic Chemistry. IUPAC Recommendations and Preferred Names 2013 has given for your problem:

Page 82, P-, example 4 on this page. Delete 1,1′-(2-ethenyl-1,2,3-trimethyldisilazane-1,3-diyl)bis(ethan-1-one).

As Igors Mihailovs (OP) pointed out in comment section to the question, the Recommendations 2013 are not error-free. You may see how nany errors have been corrected in this web page. For example, page 75 has 4 errors in that page alone!

  • $\begingroup$ That error list on the web page struck me like a lightning bolt :-0 $\endgroup$ Apr 7, 2020 at 19:04
  • 1
    $\begingroup$ I actually had another subquestion about that structur, as to why there is locant 1 cited in the "ethane-1-one", but multiple corrections on the page You cited confirmed this is ANOTHER bug in this name. $\endgroup$ Apr 7, 2020 at 19:09

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.