Shanxian Chemical
SUPPLEMENTS
Covalent or Hydrogen Bond Stronger
On the strength of covalent bonds and hydrogen bonds
Those who talk about chemical bonds often debate the strength of covalent bonds and hydrogen bonds. Covalent bonds, atoms are connected by shared electron pairs, and their formation is also derived from the tendency of atoms to achieve a stable electronic structure. The electron pairs closely hold the atoms to form a strong structure. The force of this bond is related to the type of atoms and the degree of electron cloud overlap. For example, in diamond, carbon atoms form a three-dimensional network with covalent bonds, resulting in excellent hardness and extremely high melting point, which shows the huge force of covalent bonds.
Hydrogen bonds are the weak interactions between hydrogen atoms and electronegative atoms (such as nitrogen, oxygen, fluorine) after combining with another electronegative large atom. Although it is called a "bond", it is actually an atypical chemical bond, which is mostly caused by uneven charge distribution between molecules. Take water as an example, hydrogen and oxygen in water molecules are connected, hydrogen is slightly positively charged, and the oxygen in adjacent water molecules is slightly negatively charged, and the two attract to form a hydrogen bond. The boiling point of water is higher, and the density of ice is less than that of water, all of which are the work of hydrogen bonds.
However, regardless of the strength of the two, the covalent bond is usually stronger than the hydrogen bond. When a covalent bond is formed, the electron pair is tightly bound between the atoms, and the energy changes significantly, and the destruction requires a large amount of energy. The essence of hydrogen bonds is weak electrostatic interaction, and the bond energy is relatively small. For example, in the structure of a protein, the amino acids in its polypeptide chain are covalently linked to form the main chain to maintain the basic structure; while the chain is interlinked by hydrogen bonds to stabilize its secondary and tertiary structures. When an external force acts, the hydrogen bond breaks first, causing the conformation of the protein to change, while the main chain covalent bond is more difficult to break.
However, there is no absolute in the world, and in specific situations, the hydrogen bond effect cannot be ignored. In some supramolecular systems, many hydrogen bonds cooperate to build a stable and orderly structure and play key functions. But overall, from the perspective of general significance and bond energy nature, the covalent bond is stronger than the hydrogen bond. This is the basic understanding of chemistry, and it is of great significance in exploring the structure and properties of matter.
Those who talk about chemical bonds often debate the strength of covalent bonds and hydrogen bonds. Covalent bonds, atoms are connected by shared electron pairs, and their formation is also derived from the tendency of atoms to achieve a stable electronic structure. The electron pairs closely hold the atoms to form a strong structure. The force of this bond is related to the type of atoms and the degree of electron cloud overlap. For example, in diamond, carbon atoms form a three-dimensional network with covalent bonds, resulting in excellent hardness and extremely high melting point, which shows the huge force of covalent bonds.
Hydrogen bonds are the weak interactions between hydrogen atoms and electronegative atoms (such as nitrogen, oxygen, fluorine) after combining with another electronegative large atom. Although it is called a "bond", it is actually an atypical chemical bond, which is mostly caused by uneven charge distribution between molecules. Take water as an example, hydrogen and oxygen in water molecules are connected, hydrogen is slightly positively charged, and the oxygen in adjacent water molecules is slightly negatively charged, and the two attract to form a hydrogen bond. The boiling point of water is higher, and the density of ice is less than that of water, all of which are the work of hydrogen bonds.
However, regardless of the strength of the two, the covalent bond is usually stronger than the hydrogen bond. When a covalent bond is formed, the electron pair is tightly bound between the atoms, and the energy changes significantly, and the destruction requires a large amount of energy. The essence of hydrogen bonds is weak electrostatic interaction, and the bond energy is relatively small. For example, in the structure of a protein, the amino acids in its polypeptide chain are covalently linked to form the main chain to maintain the basic structure; while the chain is interlinked by hydrogen bonds to stabilize its secondary and tertiary structures. When an external force acts, the hydrogen bond breaks first, causing the conformation of the protein to change, while the main chain covalent bond is more difficult to break.
However, there is no absolute in the world, and in specific situations, the hydrogen bond effect cannot be ignored. In some supramolecular systems, many hydrogen bonds cooperate to build a stable and orderly structure and play key functions. But overall, from the perspective of general significance and bond energy nature, the covalent bond is stronger than the hydrogen bond. This is the basic understanding of chemistry, and it is of great significance in exploring the structure and properties of matter.
Scan to WhatsApp
