# How do you pronounce \rightleftarrows?

I'm making a latex to speech library, and I have come across

\rightleftarrows


which looks like this:

⮂


which is in context to this equation:

\rm CO_2 + H_2O \rightleftarrows H_2CO_3 \rightleftarrows HCO_3^- + H^+


I tried looking for the symbol in Larry's speakeasy, which is a guide to verbalizing math, but that symbol was not in there.

Rather than simply saying, Right Left Arrows. , is there better terminology for this symbol?

• That's the wrong arrow for the context: you want an equilibrium arrow, which is 'half' in each direction – Joseph Wright Feb 3 '17 at 8:20
• Yes: my 'day job' is as a chemistry lecturer! – Joseph Wright Feb 3 '17 at 8:22
• On the arrows business, chemistry.stackexchange.com/questions/20127/… covers it (though it's very rare to see ⇄). On the main part of your question, I have a feeling it's off-topic as it's not really TeX related. For a chemistry context you'd read the equation as something like 'carbon dioxide plus water is in equilibrium with carbonate and protons'. – Joseph Wright Feb 3 '17 at 8:31
• chemically speaking, "reacts in both directions" is not entirely wrong, but the proper terminology is still "in equilibrium with" – Xylius Feb 3 '17 at 9:24
• Taking into account some of the comments on your previous related question I think you're going to end up needing a significant option on this library: What it's talking about, e.g. Chemistry/Physics/Maths (you'll almost certainly need to subdivide at least some of these) as a particular symbol's meaning will differ (even if used properly e.g. \rightarrow, but more significantly they're not always used properly . I suggest a "read the symbol name" variant as well (even if you decide not to implement field-specific meanings yet) – Chris H Feb 3 '17 at 9:48

which can be displayed using \leftrightharpoons