Double harpoon arrow for type chemistry

How can set how long make the arrow for Chemical Equation ?

How can type “double arrows” (one right and one left over the right ,harpoon or any else style ) for type chemical balance?

In your example PDF the arrows are actually images.

All the DejaVu fonts have these harpoon arrows.
You can use the Special Characters dialog to insert them.

Here is an example of DejaVu Serif:


Verajja Serif is a derivative of DejaVu Serif (BitStream Vera Serif).
Basically the same font, but it’s arrows are slimmer.


Vollkorn also has them.


These are all free fonts. There may be others …


If this answered your question please check the checkmark at left.


Thank you for your Help!

you can use dlrarrow for it

No i dont mean this …
look in this link what i mean , what i want …
link text

The best you can do in Math is to insert the double arrow as a symbol: ⇌ U+21CC

2 "H"_2 "O" oper ⇌ "H"_3 "O"^"+" + "OH"^"-"

I used oper to turn the double arrow into an operator.

Thank you for your Answer!