What is the Difference Between Ammonia and Boron Trifluoride

The key difference between ammonia and boron trifluoride is that ammonia is a polar molecule, whereas boron trifluoride is a nonpolar molecule.

Ammonia and boron trifluoride have similar atomicity and closely similar connectivity of atoms, but there is a lone electron pair on the nitrogen atom in ammonia molecule while there are no lone electrons on the boron atom in boron trifluoride. This fact makes ammonia a polar molecule and boron trifluoride a nonpolar molecule.

CONTENTS

1. Overview and Key Difference
2. What is Ammonia 
3. What is Boron Trifluoride
4. Ammonia vs Boron Trifluoride in Tabular Form
5. Summary

What is Ammonia?

Ammonia is an inorganic compound having the chemical formula NH₃. It is a gaseous substance and is the simplest pnictogen hydride. Ammonia occurs as a colourless gas having a pungent, irritating odour. The IUPAC name of Ammonia is azane. The molar mass of ammonia is 17.03 g/mol. Its melting point is −77.73 °C, and its boiling point is −33.34 °C.

When considering the occurrence of ammonia gas, it naturally occurs in the environment but in trace amounts as a product of nitrogenous animal and vegetable matter. Sometimes, we can find ammonia in rainwater as well. Inside our body, kidneys secrete ammonia to neutralize excess acid.

The chemical structure of the ammonia molecule has a nitrogen atom bound to three hydrogen atoms. Since there are five electrons in the outermost electron shell of nitrogen, there is a lone electron pair on the nitrogen atom of the ammonia molecule. Hence, the geometry of the ammonia molecule is trigonal pyramidal. Furthermore, we can liquefy this compound easily. This is because it is capable of forming hydrogen bonds between ammonia molecules since there are N-H bonds and lone electron pairs as well.

What is Boron Trifluoride?

Boron trifluoride is an inorganic compound having the chemical formula BF3. It is a pungent gas that is colourless and toxic. It can form white fumes in moist air. However, there are two major forms of boron trifluoride as anhydrous form and dihydrate form; the anhydrous form is a colourless gas, while dihydrate form is a colourless liquid. When considering their solubility in water, anhydrous form tends to undergo exothermic decomposition when added to water, whereas the dihydrate form is highly water-soluble. This substance is corrosive, so we need to use stainless steel, Monel, and Hastelloy for storage of this substance.

Boron trifluoride molecule has trigonal planar geometry. It has no dipole moment because of its symmetry. This molecule is isoelectronic with carbonate anion. In common terms, we call boron trifluoride an electron-deficient chemical species. It has an exothermic reactivity with Lewis bases.

In the synthesis of boron trifluoride, we can produce it from the reaction between boron oxides and hydrogen fluoride. However, in laboratory needs, we can produce boron trifluoride using boron trifluoride etherate (a commercially available liquid).

What is the Difference Between Ammonia and Boron Trifluoride?

Ammonia and boron trifluoride are 4-atom molecules, both having a central atom bonded to three other atoms. However, unlike in the boron trifluoride molecule, there is a lone electron pair in the ammonia molecule, which makes it polar. Therefore, the key difference between ammonia and boron trifluoride is that ammonia is a polar molecule, whereas boron trifluoride is a nonpolar molecule.

The following infographic lists the difference between ammonia and boron trifluoride in tabular form for side by side comparison.

Summary – Ammonia vs Boron Trifluoride

Ammonia is an inorganic compound having the chemical formula NH_3, while Boron trifluoride is an inorganic compound having the chemical formula BF3. The key difference between ammonia and boron trifluoride is that ammonia is a polar molecule, whereas boron trifluoride is a nonpolar molecule.

Reference:

1. “Synthesis of Ammonia: Process & Reaction.” Study.com

Image Courtesy:

1. “Ammonia-2D” By Radio89 – Own work (CC BY-SA 3.0) via Commons Wikimedia
2. “Boron-trifluoride-2D-dimensions” By Ben Mills – Own work (Public Domain) via Commons Wikimedia