Is hydroxide −OH or HO−?

1 Answer
Truong-Son N.
Jan 1, 2017

It doesn't matter.

Depending on how you draw an entire molecule that contains −OH, you may want to draw it as HO− to emphasize that that's how the structure is drawn, but there is no set rule saying it must be −OH instead of HO−.

Examples:

You can write methanol as CH3OH to emphasize that the −OH is drawn as −O−H instead of H−O−:

Or, you can write ethanediol as HOCH2CH2OH to emphasize that the structure is H−O−CH2−CH2−O−H:

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