Basic characteristics of various chemical bonds

    The basic characteristics of various chemical bonds are briefly described as follows:
1. Ion-bonding Ionic bonds are formed by electron transfer (the electrons are cations and the electrons are anions). That is, the chemical bond formed between the positive ion and the negative ion due to electrostatic attraction.
The ionic bond has strong force, no saturation, and no directionality. Minerals formed by ionic bonds are always present in the form of ionic crystals.
2. The formation of covalent bond covalent bond is the pairing of electrons with opposite spin directions between two adjacent atoms. At this time, the atomic orbitals overlap each other, and the density of electron clouds between the two nuclei increases relatively, thereby increasing the two nuclei. Gravity. This bond force combined in an atomic state is called a covalent bond. The covalent bond has a strong force, saturation and directionality.
3. Since the metal key in the metal lattice free electrons exist, the entire metal atom crystals (or ions) with the free electrons to form a chemical bond. This type of key has a weaker force and has no directionality and saturation.
4. Molecular bond The molecular bond is caused by three forces, namely the rotation effect, the induction effect and the dispersion effect.
1) The rotation effect is an intermolecular electrostatic attraction caused by dipole rotation between molecules having a permanent dipole moment.
2) The inductive effect is that when one dipole encounters another polarized molecule, the molecule is induced to generate a dipole, so that the two dipole molecules attract.
3) Dispersion effect, for the original dipole molecule, the nucleus and electrons inside the molecule continuously move to produce dispersive force; for the molecule without permanent dipole, due to the vibration of the nucleus and the continuous movement of electrons, an instantaneous dipole is generated. The attractive force generated by the instantaneous dipole is also called the dispersive force.
Intermolecular forces have no directionality and saturation, and the bond strength is weak.
5. The formation of hydrogen-bonded hydrogen bonds is due to the fact that hydrogen atoms and electron-positive X atoms (such as F, O, N atoms) are covalently bonded, and the shared electron pair is strongly biased toward the X atom, making the hydrogen nuclei almost "Naked" out. This "naked" hydrogen nucleus, because of its small size and without internal electrons, is not easily repelled by electron clouds of other atoms, so it can also attract another Y atom with higher electronegativity (such as F, O). , a separate electron cloud in the N atom) forms a hydrogen bond.
X-H...Y
The dotted line in the formula represents a hydrogen bond. X, Y can be the same element or different elements.

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