Are S2Cl2 and SCl the same thing?

[ooookkkkk]

Homework Statement

why do we write S2Cl2 instead of SCl?

Relevant Equations

no

I think S2Cl2 and SCl are the same thing, and SCl actually simpler and concise, so why do we have disulfur dichloride ?

 

[TeethWhitener]

Yes they’re (unfortunate) synonyms, especially as SCl and S₂Cl₂ both exist as distinct species. But SCl is an unstable short-lived species, whereas S₂Cl₂ is a stable (albeit somewhat reactive) liquid. Generally when people use “sulfur chloride” they’re referring to S₂Cl₂, but it’s more clear and correct to refer to it as disulfur dichloride (note: “sulfur dichloride” isn’t good enough, since SCl₂ is yet another chemical compound).

 

[Borek]

I wouldn't say they are the same. Just because compounds have the same empirical formula doesn't mean they are identical. The final formula reflects the molar mass.

By applying the same logic every alkene and cycloalkane would be the same compound with the formula CH₂. Yet they are very different.

 

[dextercioby]

By what theoretical model, would the compound $\text{SCl}$ be possible? The elementary (non-quantum) of G. Lewis obviously not, since it would imply an unbalanced number of electrons either with a simple, or with a double bond. It should be a quantum-like model, with some partial charges (plus delta on the sulphur and minus delta on the chlorine) from sharing an electron. That would make it extremely unstable and prone to dimerization around sulphur, case in which the dimer structure could be accepted even in a Lewis theory (three simple bonds $\text{Cl}-\text{S}-\text{S}-\text{Cl}$).

 

[TeethWhitener]

By what theoretical model, would the compound $\text{SCl}$ be possible? The elementary (non-quantum) of G. Lewis obviously not, since it would imply an unbalanced number of electrons either with a simple, or with a double bond. It should be a quantum-like model, with some partial charges (plus delta on the sulphur and minus delta on the chlorine) from sharing an electron. That would make it extremely unstable and prone to dimerization around sulphur, case in which the dimer structure could be accepted even in a Lewis theory (three simple bonds $\text{Cl}-\text{S}-\text{S}-\text{Cl}$).

You're right, it's a radical with an unpaired electron, so Lewis theory can't really handle it well. Radicals tend to be very reactive and/or unstable (there are exceptions, but SCl isn't one of them). There doesn't look to have been much work done on it recently, but it appeared for a while in the atmospheric chemistry literature. Examples:
https://pubs.rsc.org/en/Content/ArticleLanding/F2/1988/F29888400067#!divAbstract
https://www.sciencedirect.com/science/article/pii/0022285286902560

 

[DrDu]

I am pretty sure that SCl has been intensively studied in the gas phase, including all its excited states. Just that you can't fill it into a bottle does not mean it is not important. For example, there are lasers operating with molecules only bound in an excited state https://en.wikipedia.org/wiki/Excimer_laser

 

[Huzaifa]

I found three Sulfur chloride chemical compounds on Wikipedia:

1. Disulfur dichloride, S2Cl2
2. Sulfur dichloride, SCl2: It is simplest and one of the most common, polar chemical compound. It has a total of 20 valence electrons, (sulfur has 6 electrons in the valence shell and chlorine has 7). It has a bent molecular geometry with bond angle and bond length approximately 103° & 201 pm respectively.
3. Sulfur tetrachloride, SCl4: It has a total of 34 valence electrons , (sulfur has 6 electrons in the valence shell and chlorine has 7). It has Disphenoidal or Seesaw molecular geometry. It is not as common as sulfur tetrafluoride SF4.