Symmetric Hydrogen Bond

When a hydrogen atom attracts an electronegative atom via dipole-dipole attraction, hydrogen bonds form. Hydrogen bonds are most commonly formed between hydrogen and fluorine, oxygen, or nitrogen. Intramolecular bonding, or bonding between atoms within a molecule, is more common than bonding between atoms of different molecules (intermolecular).

Intramolecular Hydrogen Bonding

• An intramolecular hydrogen bond occurs when a hydrogen connection exists within a molecule itself.
• The two groups of compounds form intramolecular hydrogen bonds, with one group containing a hydrogen atom connected to an electronegative atom.
• A strongly electronegative atom from one group is bonded to a less electronegative atom from the other group.

Intermolecular Hydrogen Bonding

•   Intermolecular hydrogen bonds occur when hydrogen bonds exist between different types of molecules in the same or separate types of substances.
• Water and alcohol are two hydrogen bonding examples.

Symmetrical Hydrogen Bonding

• This symmetrical hydrogen bonding connection is unique in that the proton is typically positioned between two identical atoms.
• The strength of each atom’s link is the same.
• The three-centre-four-electron symmetrical hydrogen bond is a type of three-centre-four-electron bond.
• It’s also a lot stronger than “regular” hydrogen bonds, and it’s practically as strong as a covalent bond.

Metallic Bonding

• Thermal conductivity, Brilliance, high electrical and ductility, malleability, gloss and high tensile power are all characteristics of metals.
• A metallic crystal consists of a huge number of atoms that are organised in a regular pattern.
• Various models for explaining the nature of metallic bonding have been presented. Mobile electrons and positive kernels, on the other hand, are the two most important. For more information, refer to the hydrogen bond notes.

What is a Symmetric Hydrogen Bond?

A symmetric hydrogen bond is one in which the proton is evenly distributed between two similar atoms. The bond between each of those atoms has the same strength. It’s a three-centre, four-electron bond. This sort of bond is substantially stronger than “regular” hydrogen bonds, and it is comparable to a covalent bond in strength. It can be found in ice as well as the solid phase of several anhydrous acids at high pressure. The bifluoride ion [FHF] also exhibits this property.

Much has been done to quantum-mechanically explain the symmetric hydrogen bond, which appears to violate the duet rule for the first shell: Four electrons effectively surround the proton. Because of this issue, some people mistake it for an ionic bond.

Properties of Hydrogen Bond

• Solubility: Because of the hydrogen bonding between an alcohol molecule and water, lower alcohols are more soluble in water.
• Volatility: Compounds containing hydrogen bonding between molecules have a lower boiling point and are therefore less volatile.
• Viscosity and surface tension: Because hydrogen bonds exist as linked molecules, substances containing hydrogen bonds are more difficult to flow, have a greater consistency or viscosity, and have a high surface tension.
• The lower density of ice than of water: A box-like shape of water molecules is formed by solid ice. Each water molecule is, in fact, tetrahedrally bonded to four other water molecules. In the solid state, the molecules are not packed as tightly as they are in the liquid state. This structure collapses when ice melts, and the molecules migrate closer together. As a result, with the same mass of water, the volume falls and the density rises. As a result, ice has a smaller density than water at 273 K. Ice floats because of this.

Hydrogen bonding Model of the Electron Sea

This model assumes that metal is made up of a lattice of positive ions (or nuclei) immersed in a sea of freely moving valence electrons. The total valence electronic charge per atom is consequently equal to the atom plus its nucleus in absolute terms.

Free electrons safeguard positively charged ions from mutual electrostatic repulsive forces that they would otherwise impose on one another. These unbound electrons operate as a “glue” to hold the ion nuclei together in this fashion.

Metallic bonds are the forces that hold atoms together in a metal due to the attraction between positive ions and the electrons that freely surround them.

Despite the fact that the electron sea is older than quantum mechanics, it nevertheless adequately describes some metal properties. The presence of mobile electrons in metals, for example, helps explain their thermal and electrical conductivity.

These flowing electrons transfer electricity across metals from one end to the other when an electron field is applied. When a piece of metal is heated, the moving electrons in that piece of metal gain a lot of kinetic energy. These electrons move swiftly across the metal and carry heat to the other side because they are free and mobile.

Conclusion

Only compounds with Hydrogen atoms linked to an electronegative atom experience a unique form of intermolecular attractive force. The Hydrogen Bond is the name for this force. In water molecules, for example, the hydrogen atom is connected to a highly electronegative Oxygen atom. As a result, symmetric hydrogen bonding is formed by dipole-to-dipole interactions between the Hydrogen atom of one molecule and the Oxygen atom of another molecule.