I came across this structure of $\ce{HF2-}$ and realized that the bond shown between H and F is a hydrogen bond.
$$\Large\ce{[F-H-F]-}$$
HF hydrogen bond are the strongest hydrogen bonds we know, but still they are not real bonds. Writing the molecular formula as $\ce{HF2-}$ will give anyone an idea that the bonds between H and F are only covalent bonds.
Why do we write the molecular formula of $\ce{HF2-}$ as this and can you throw more light on its structure? Have I correctly understood the structure?
Answer
There is no such distinction as "real" vs "not-so-real" bond. Hydrogen bonds are as real as any other bonds (although weaker than many), and this particular one, as you already know, is the strongest of all hydrogen bonds.
As to why we write the formula this way, the answer is simple: because it is this way. We fool around with some fluoride compounds, and then we find out this one; we analyze it, and it seems to contain K, H, and F, and the composition turns out to be $\ce{KHF2}$. Before we know anything about hydrogen bonding, or chemical bonding whatsoever, we already have the reason to write the formula the way it is. Then X-ray crystallography comes along, so we can actually look at it, and see it is really this way; it really does contain those $\ce{HF2-}$ anions.
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