I've read the story of Karen Wetterhahn and how she was poisoned and died from two drops of dimethylmercury that accidentally fell on her latex glove, and I was wondering what is the chemical explanation for such easy penetration of the compound through latex and skin. I do not have a vast knowledge of heavy metal chemistry, but here are the points that gave rise to this question:

  1. There are many dimethyl compounds with a similar structure to dimethylmercury. Some are very common, such as dimethyl ether (CH3-O-CH3), propane (CH3-CH2-CH3). Oxygen is a lot smaller than mercury, and methylene is larger but is (presumably, I might be wrong here) more similar to the methyl groups than mercury in hydrophobicity etc., so why are they not as penetrative?
  2. According to this answer by AMM:

Actually metallic mercury is very hard to absorb by ingestion or through the skin so if ingested one will most likely survive (according to studies on animals). However, if one ingests the same amount in a soluble salt form (or any other absorbable form, eg HgMe2) he is in serious trouble (see here: Karen Wetterhahn).

Is it because the most common form of mercury is the cation $Hg^{2+}$, whereas the methyl groups make the compound uncharged and thus soluble in hydrophobic matter, such as skin and latex?

  • 1
    $\begingroup$ Yes, that's pretty much the size of it. $\endgroup$ Oct 31 '18 at 11:08
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    $\begingroup$ I'm not sure rate of skin absorption is the problem. For one thing, I can't find skin absorption values for HgMe2 to make a comparison. Nevertheless, a crucial difference is that if your skin comes into contact with 0.1 mL of HgMe2, your life is in serious danger, whereas 0.1 mL of dimethyl ether or propane on the skin (well these are gases but still), no matter how efficiently these penetrate the skin, you aren't going to feel it—your body takes care of it. As for why HgMe2 kills you so easily? Try reading sections 1 and 3 here: en.wikipedia.org/wiki/Methylmercury $\endgroup$
    – Blaise
    Oct 31 '18 at 16:09

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