What is Molecular Geometry?
Molecular geometry refers to the arrangement of atoms in a molecule, which is usually relative to a single central atom. It excludes lone pairs from determining the shape of a molecule, though repulsion from lone pair(s) is considered only in bond angles.
Bond lengths, bond angles, and torsional angles are geometrical parameters that help determine the position of atoms as well as the overall shape of a molecule. It influences a substance’s properties such as reactivity, colour, polarity, magnetism, biological activity, and phase of matter.
What is Linear Molecular Geometry?
Linear molecules are molecules that are straight and have a bond angle of 180 degrees. These molecules are made up of a central atom that is bonded to two other atoms via single or double bonds (sometimes there can be triple bonds as well). Furthermore, the central atom usually can have either 0 or 3 lone electron pairs (AX2 or AX2E3) in the AXE notation.
Table of Contents
- Linear Molecular Geometry Bond Angle
- Linear Molecular Geometry Lone Pairs
- Linear Molecular Geometry Examples
- Linear Molecular Geometry Polarity
- Linear Molecular Geometry Hybridization
- Difference Between Linear Molecular geometry and Bent Molecular Geometry
- Frequently Asked Questions – FAQs
Linear Molecular Geometry Bond Angle
The geometry described by linear molecular geometry revolves around a central atom that is bonded to two other atoms (or ligands) at a bond angle of 180°.
Linear Molecular Geometry Lone Pairs
The five valence electron pairs on the central atom form a trigonal bipyramid, with the three lone pairs occupying the less crowded equatorial positions and the two bonded atoms occupying the two axial positions at opposite ends of an axis, forming a linear molecule.
| No. of Bond pairs | No. of Lone pairs | Molecular Type | Electron Geometry | Molecular Geometry |
|---|---|---|---|---|
| 2 | 0 | AX2 |  |
|
| 2 | 3 | AX2E3 |  |
|
Read more:Molecular Geometry and Electron Geometry
Linear Molecular Geometry Examples
Neutral AX2 molecules include-
- Carbon dioxide (the central atom is carbon, and two oxygen atoms are bonded to the carbon atom via double bonds, forming a nonpolar compound).
- Acetylene (contains a triple bonded carbon moiety bonded to two hydrogen atoms via single bonds, forming a linear molecule).
- Hydrogen cyanide (contains a central carbon atom bonded to one hydrogen atom via a single bond and to one nitrogen atom via double bonds).
AX2E3 type molecules include-
- Xenon Flouride XeF2
- Triiodide ion [I3]–
Linear Molecular Geometry Polarity
If the two bonded atoms are identical, the polarity of this type of molecule is zero. A polar compound is formed when two different atoms are bonded to a central atom in the form of a linear molecule. Since it has two bonded atoms, the central atom has a coordination number of two.
Linear Molecular Geometry Hybridization
The linear structure of molecules can be explained by sp hybridization. In it, the 2s orbital and one of the 2p orbitals combine to form two sp orbitals, each with 50% s and 50% p character. The two orbitals are separated by a 180° angle formed by the front lobes facing away from each other. This structure reduces electron repulsion.
Difference Between Linear Molecular geometry and Bent Molecular Geometry
The main difference between linear and bent molecules is that linear molecules have atoms that are bonded to each other to form a straight molecule, whereas bent molecules have atoms arranged in a bent shape with an angle. In addition, linear molecules are straight molecules with a bond angle of 180 degrees, whereas bent molecules are angular molecules with a bond angle less than 180 degrees.
Read more: Bent Molecular Geometry
Frequently Asked Questions on Linear Molecular Geometry
Which molecule has a linear molecular geometry?
A linear molecule is one in which the atoms are arranged in a straight line (less than a 180° angle). The sp hybridization occurs at the central atom of molecules with linear electron-pair geometries. Carbon dioxide (O=C=O) and beryllium hydride BeH2 are examples of linear electron pairs and molecular geometry.
How do you know if a molecule is linear?
If a molecule’s chemical structure has linear geometry that appears to be a straight line, it is a linear molecule.
What is the electron geometry of a molecule with linear molecular geometry and AX2E3 notation?
The electron geometry of a molecule with linear molecular geometry and AX2E3 notation is trigonal bipyramidal. An example of such a molecule is XeF2.
What is the difference between bent molecular geometry and linear molecular geometry?
The main difference between linear and bent molecules is that in linear molecules, the atoms are bonded to each other, forming a straight molecule with an angle of 180°, whereas in bent molecules, the atoms are arranged in a bent shape with an angle less than 180°.
Are molecules with linear molecular geometry polar or non-polar?
The polarity of this type of molecule is zero if the two bonded atoms are identical. When two different atoms are bonded to a central atom in the form of a linear molecule, a polar compound is formed.
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