from Wiktionary, Creative Commons Attribution/Share-Alike License
- adj. of, or relating to a pentad
from The Century Dictionary and Cyclopedia
- In chem., pentavalent.
Sorry, no etymologies found.
The second point is that an objection may be urged, as, for example, in ammonium chloride (the lecturer stated above that here N was a pentad, the addition of the chlorine having caused the N to assume the pentadic character), it may be said, why should you not suppose that it is the chlorine "which has altered its valency, and that the compound should be written: