Is selenium disulfide polar or non-polar? So I saw in some internet site that $\ce{SeS2}$ is a polar molecule. When I drew the Lewis structure of the molecule, it showed up as a linear molecule like this:
$$\ce{S=Se=S}$$
The electronegativity difference of $\ce{Se-S}$ is just $0.01$ and the linear form shows that vectors cancel each other. Yet, some websites state that this molecule is polar, when everything to me indicates is a non-polar molecule.
Are they wrong or am I missing something here?
I understand your assumption of selenium disulfide being a simple molecular like that. It is similar to the mistake of silicon dioxide, which at first glance we might assign it to be a linear molecule like carbon dioxide. However the crystal structure of silicon dioxide is far more complex.
In selenium disulfide, the selenium and sulfur atoms form a 8-membered ring, similar to the 8-member rings you would find in certain allotropes of either elemental selenium or elemental sulfur. The ratio of $\ce{Se:S}$ atoms is not exactly $\mathrm{1:2}$ as the chemical formula implies (that would give $\mathrm{\frac{8}{3}}$ atoms of $\ce{Se}$ and $\mathrm{\frac{16}{3}}$ atoms of $\ce{S}$ per ring). Indeed the ratio is closer to $\mathrm{3:5}$ ($\mathrm{3:6}$ is $\mathrm{1:2}$ anyways). A better representation of the compound is $\ce{Se_{n}S_{8-n}}$.