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A molecular geometry model with one atom in the centre and three atoms at the corners of an equilateral triangle, called peripheral atoms, all on one plane is known as trigonal planar in chemistry.It’s ideal for all three ligands to be the same, and all bond angles to be 120° . Three sp2 hybrid orbitals are evenly spaced in this molecule. The orbitals have a flat triangle form. Because each orbital has one atom at the end, the molecule’s form is also planar triangular.
Trigonal pyramidal:
NH3 is an example of trigonal pyramidal molecular geometry that derives from tetrahedral electron pair geometry. Due to its five valence electrons, nitrogen requires three additional electrons from three hydrogen atoms to complete its octet. This leaves a lone electron pair with no other atom with which to form a bond. The three hydrogen atoms and the lone electron pair are as far apart as they can be with a 109o bond angle. Tetrahedral electron pairs have this geometry. The lone electron pairs repel the three connected hydrogen atoms a little more, resulting in a slight compression to a 107o bond angle. The molecule is three-dimensional, unlike the boron hydride molecule, which has a flat trigonal planar molecular geometry due to the absence of a lone electron pair.
Trigonal Planar hybridization:
Trigonal pyramidal is a chemical form that occurs when the central atom in the molecule has three bonds and one lone pair. Sp3 hybridization occurs at the centre atom of molecules with tetrahedral electron pair geometries. The molecule ammonia (NH3) has a trigonal pyramidal shape.
Feature of trigonal planar geometry:
- This molecule is made up of three equally spaced sp2 hybrid orbitals placed at 120o angles, which is a feature of trigonal planar geometry.
- The orbitals have a flat triangle form.
- Because each orbital has an atom at the end, the molecule’s shape is also trigonal planar.
- The general formula in this geometry is AX3. All four atoms are arranged on a single plane.
- D3h is the trigonal planar geometry point group.
- Example BF3, BCl3, AlCl3, SO3, AlF3 etc.
Trigonal planar shape examples:
Boron trifluoride (BF3) and boron trichloride (BCl3) are examples of sp2 trigonal planar molecular geometry.
The core boron atom is connected to three other atoms in both circumstances, and there are no lone pairs.
Molecular geometry of BF3:
The molecule of BF3 has a ‘Trigonal Planar’ geometry. ‘Trigonal Planar,’ according to the Chemistry reference, is a model with three atoms surrounding one atom in the middle. It’s like having all of your peripheral atoms in one spot, because all three of them have the same 120° bond angles, making them an equilateral triangle. The overlap between the two compounds is primarily responsible for the flat triangle geometric shape. It is also nonpolar and has a symmetric charge distribution on the centre atom. When all of the atoms are in one spot, the bond angle is 120°. An equilateral triangle is formed by the molecular geometry and bond angles of BF3.
Lewis BF3‘s structure On the basis of hybridization, the structure of the BF3 molecule is revealed. To figure out the BF3 Lewis structure, we must count the total number of valence electrons in the molecule. The centre atom of BF3 has a maximum of 24 valence electrons, which we must arrange around it. Before you start completing the octets, make sure you know how many valence electrons are in Boron Trifluoride and where they should go. Boron settles at the structure’s core since it is the least electronegative element. In its outer shell, it requires six valence electrons. Even though Boron only has six valence electrons, we can see that the formal charges for the Boron Trifluoride Lewis structure are zero.
Conclusion:
A trigonal planar molecular geometry compound has a centre atom that is bonded to three additional atoms or groups. The three groups to which it is connected form a triangle around the core atom, with bond angles of 120 degrees, because it has no lone pairs of electron pairs.
