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Why does water have a higher boiling point than hydrogen sulfide and ammonia?

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water rapids, Niagara Falls, Canada — water Water is the most plentiful compound on Earth and is essential to life. Although water molecules are simple in structure (H₂O), the physical and chemical properties of water are extraordinarily complicated.

Water has a significantly higher boiling point than hydrogen sulfide and ammonia primarily due to extensive hydrogen bonding between its molecules.12

While water, ammonia, and hydrogen fluoride exhibit strong hydrogen bonding, these interactions are absent or significantly weaker in their heavier analogues, such as hydrogen sulfide and phosphine. In the liquid state, water molecules are held together by these strong intermolecular forces, which require substantial thermal energy to overcome during the process of vaporization.12

Without this extensive network of hydrogen bonds, water would be expected to have a boiling point nearly 200 °C (360 °F) lower than its observed value, given the small size of its molecules. Consequently, the high boiling point of water is a direct result of the energy required to break these hydrogen bonds to permit the transition from a liquid to a gaseous state.21