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[✓] Errors in some ChemicalData isomeres?

Posted 6 months ago
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I was trying to get
ChemicalData["C18H30O2", "MolarMass"]

which returns 9 values
{277.43g/mol,277.43g/mol,277.43g/mol,277.43g/mol,278.44g/mol,278.44g/mol,278.44g/mol,278.44g/mol,278.44g/mol}
of which only last 5 are right.

Looking why this could happen, it seems like Mathematica tries to get all known isomeres for "C18H30O2" but apparently several of them have invalid data.

That is, ChemicalData["C18H30O2"] returns
{crepenynate,alpha-eleostearate,calendate,punicate,linolenic acid,1,2-dihexyloxybenzene,11-trans-13-trans-15-cis-octadecatrienoic acid,gamma-linolenate,4-dodecylresorcinol}
Which is right, but again Map[ChemicalData[#, "MolarMass"] &, ChemicalData["C18H30O2"]]
gives wrong molar masses
{277.43g/mol,277.43g/mol,277.43g/mol,277.43g/mol,278.44g/mol,278.44g/mol,278.44g/mol,278.44g/mol,278.44g/mol}

2 Replies

Thanks for pointing this out. The issue seems to stem from

In[27]:= Entity["Chemical", "Crepenynate"]["FormulaString"]

Out[27]= "C18H30O2"

In[26]:= Entity["Chemical", "Crepenynate"]["VertexTypes"] // Tally

Out[26]= {{"C", 18}, {"O", 2}, {"H", 29}}

In this case, the "Formula" is entered incorrectly, which led to this entity being in the "C18H30O2" entity class. I will file a bug report.

Posted 6 months ago

Thanks! FormulaString is right, vertices are wrong. Whatever, I imagine this can be scanned and compared.

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