# How can the hydrogen bonds in solid HF be best represented?

The hydrogen bonds in solid HF can be best represented as:

The correct answer is supposed to be (c), but I don't understand why this is so. Does the strength of hydrogen bonding depend on the $$\ce{F-H\bond{...}F}$$ or the $$\ce{H-F\bond{...}H}$$ bond angles?

• Of course it does depend. That's one of most important things about hydrogen bonds. – Mithoron Feb 27 '20 at 2:02

Generally hydrogen bonds $$\ce{A-H\bond{...}B}$$ can be taken to be approximately linear.
In fact, the highest bonding energy for the hydrogen bond is obtained when the two electronegative atoms (fluorine here) are approximately in line with the electropositive hydrogen atom in between ($$\ce{O\bond{...}H-O}$$ in water, $$\ce{F\bond{...}H-F}$$ in hydrogen fluoride). Deviations from linearity will reduce the bonding energy rapidly. It follows that the "best" hydrogen bond is "close" to linear.