Shanxian Chemical
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What Forms A Hydrogen Bond
On the formation of hydrogen bonds
All things in the world have complex interactions, and the formation of hydrogen bonds is unique. It is not random and has specific rules.
When a hydrogen atom is combined with an atom with a large electronegativity and a small radius (such as fluorine, oxygen, and nitrogen) in a covalent bond, the hydrogen atom is partially positively charged because the electron pair in the covalent bond is biased towards the atom with a large electronegativity. At this time, if there is another atom with a large electronegativity and a lone pair of electrons nearby, there will be a strong electrostatic attraction between the two, which is the reason for the formation of hydrogen bonds.
For example, in water, hydrogen and oxygen in water molecules are connected by covalent bonds. Oxygen is highly electronegative, hydrogen is partially positively charged, and the oxygen atoms of adjacent water molecules contain lone pairs of electrons, so hydrogen bonds are formed between water molecules. The existence of this hydrogen bond makes the boiling point and melting point of water different from common sense, which is of great significance to the origin and maintenance of life. Another example is ammonia molecules, which have high electronegativity of nitrogen. After bonding with hydrogen, hydrogen has a partial positive charge, and hydrogen bonds can be formed between ammonia molecules due to the electrostatic attraction of lone pairs of electrons of nitrogen and hydrogen.
It can be seen that the formation of hydrogen bonds requires hydrogen atoms to bond with specific electronegative atoms first, and nearby electronegative large atoms containing lone pairs of electrons, which complement each other to create hydrogen bonds. This unique intermolecular force has a profound impact on the physical and chemical properties of substances.
All things in the world have complex interactions, and the formation of hydrogen bonds is unique. It is not random and has specific rules.
When a hydrogen atom is combined with an atom with a large electronegativity and a small radius (such as fluorine, oxygen, and nitrogen) in a covalent bond, the hydrogen atom is partially positively charged because the electron pair in the covalent bond is biased towards the atom with a large electronegativity. At this time, if there is another atom with a large electronegativity and a lone pair of electrons nearby, there will be a strong electrostatic attraction between the two, which is the reason for the formation of hydrogen bonds.
For example, in water, hydrogen and oxygen in water molecules are connected by covalent bonds. Oxygen is highly electronegative, hydrogen is partially positively charged, and the oxygen atoms of adjacent water molecules contain lone pairs of electrons, so hydrogen bonds are formed between water molecules. The existence of this hydrogen bond makes the boiling point and melting point of water different from common sense, which is of great significance to the origin and maintenance of life. Another example is ammonia molecules, which have high electronegativity of nitrogen. After bonding with hydrogen, hydrogen has a partial positive charge, and hydrogen bonds can be formed between ammonia molecules due to the electrostatic attraction of lone pairs of electrons of nitrogen and hydrogen.
It can be seen that the formation of hydrogen bonds requires hydrogen atoms to bond with specific electronegative atoms first, and nearby electronegative large atoms containing lone pairs of electrons, which complement each other to create hydrogen bonds. This unique intermolecular force has a profound impact on the physical and chemical properties of substances.
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