# Ring compounds of non-carbon atoms [closed]

Are there compounds that are rings of non-carbon atoms, say a ring of six oxygen atoms, or 5-6 nitrogen atoms with attached hydrogens? Or are these too unstable to exist for long (if at all), like long oxygen chains ($\ce{HO_{n}H}$)?

## closed as too broad by Jan, M.A.R., jerepierre, ringo, Klaus-Dieter WarzechaJun 18 '16 at 4:42

Please edit the question to limit it to a specific problem with enough detail to identify an adequate answer. Avoid asking multiple distinct questions at once. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

• – Jan Jun 17 '16 at 17:30
• Are you looking for a single element around the ring? Otherwise borazine would count: en.wikipedia.org/wiki/Borazine – jerepierre Jun 17 '16 at 17:32
• Sulphur forms many cyclic allotropes, and phosphorous has some as well. – bon Jun 17 '16 at 17:34
• There are many common rings with more than one element in them and no carbons. Single element rings seem harder. – matt_black Jun 17 '16 at 19:22
• Good answers so far. Anyone know anything about rings of Oxygen? It wouldn't be aromatic since there wouldn't be any bonds left over. Right? – Justsalt Jun 17 '16 at 19:44

Pentazole exists - an $\ce{N5H}$ ring. It is stabilised by aromaticity, with 6 $\pi$-electrons in a cyclic, planar system.

Sulphur forms many allotropes which are rings but these do not contain hydrogen. $\ce{S8}$ and $\ce{S7}$ are the most common.

Phosphorus also forms cyclic allotropes such as white phosphorous, $\ce{P4}$.

DavePhD also mentioned in his answer that a silicon analogue of benzene has been synthesised recently but it is not $\ce{Si6H6}$ because it has other groups attached to some of the silicon atoms.

• Pentazole does not quite exist. I mean, well, it kinda does, but that's not quite the same kind of "exists" as benzene or anything... – Ivan Neretin Jun 17 '16 at 20:03
• I doubt that counting lone pairs in pentazole is good idea here. Also many substituted ones are more stable. – Mithoron Jun 17 '16 at 21:36
• Not 10 $\pi$ electrons. Only six, isoelectronic with pyrrhole. – Oscar Lanzi Jun 17 '16 at 23:31
• @OscarLanzi Oh yes sorry my mistake. – bon Jun 18 '16 at 8:21
• You can also have $S_8$: upload.wikimedia.org/wikipedia/commons/thumb/f/f1/… – timaeus222 Jun 18 '16 at 21:06

Chemists in the UK have constructed a structural analogue of benzene made from silicon atoms. The molecule is not flat like benzene, but it reveals a new type of aromatic stabilisation.

Do not forget the trihydrogen cation (https://en.wikipedia.org/wiki/Trihydrogen_cation, https://en.wikipedia.org/wiki/Triatomic_hydrogen). This has been found in the interstellar medium and in hydrogen-rich planetary atmospheres, and is believed to be responsible for the formation of early-generation stars.

• The trihydrogen cation is an interesting case. Though you can draw a triangular ring between the nuclei, as far as I understand the highest electron density is actually at the centre of the resulting triangle, so you could think of it more like three atoms joined by a Y-shaped bond than a ring. – Nicolau Saker Neto Jun 18 '16 at 2:00