Phosphorus Pentachloride

Definition

Phosphorus pentachloride is a covalent inorganic compound with the chemical formula PCl5. It is an important intermediate in the production of various phosphorus-containing compounds and plays a significant role in the context of hybrid atomic orbitals and the occurrence, preparation, and properties of phosphorus.

5 Must Know Facts For Your Next Test

1. Phosphorus pentachloride is a colorless, crystalline solid at room temperature, with a pungent odor.
2. It is a highly reactive compound that readily undergoes hydrolysis in the presence of water, forming phosphoric acid and hydrogen chloride.
3. The central phosphorus atom in phosphorus pentachloride has a trigonal bipyramidal molecular geometry, which is an example of $sp^3d$ hybridization.
4. Phosphorus pentachloride is an important precursor in the production of various organophosphorus compounds, such as pesticides and flame retardants.
5. The compound is also used as a chlorinating agent and a dehydrating agent in organic synthesis.

Review Questions

• Explain the molecular geometry and hybridization of the phosphorus atom in phosphorus pentachloride.
  • The phosphorus atom in phosphorus pentachloride (PCl5) has a trigonal bipyramidal molecular geometry, which is an example of $sp^3d$ hybridization. In this configuration, the phosphorus atom forms five covalent bonds with the chlorine atoms, resulting in a total of five bonding pairs of electrons and no lone pairs. The trigonal bipyramidal arrangement minimizes the repulsion between the bonding pairs of electrons, leading to a stable molecular structure.
• Describe the chemical properties and reactivity of phosphorus pentachloride.
  • Phosphorus pentachloride is a highly reactive compound due to the presence of the central phosphorus atom with an incomplete octet configuration. It readily undergoes hydrolysis in the presence of water, forming phosphoric acid (H3PO4) and hydrogen chloride (HCl). This reaction is an example of the compound's strong Lewis acidic nature, as the phosphorus atom can accept electron pairs from water molecules. Additionally, phosphorus pentachloride is commonly used as a chlorinating agent and a dehydrating agent in organic synthesis, reflecting its versatile reactivity.
• Discuss the importance of phosphorus pentachloride in the context of the occurrence, preparation, and properties of phosphorus.
  • Phosphorus pentachloride is a significant intermediate in the production of various phosphorus-containing compounds, including organophosphorus compounds like pesticides and flame retardants. The compound's unique molecular structure and reactivity make it a valuable tool in the chemical industry. Furthermore, the study of phosphorus pentachloride's properties, such as its hybridization and molecular geometry, provides insights into the broader understanding of phosphorus and its chemical behavior. This knowledge is crucial in the context of the occurrence, preparation, and properties of phosphorus, as it helps to elucidate the fundamental principles governing the behavior of this essential element.

Related terms

Phosphorus: Phosphorus is a chemical element with the symbol P and atomic number 15. It is an essential mineral found in all living cells and plays a crucial role in various biological processes.

Covalent Bond: A covalent bond is a chemical bond that involves the sharing of one or more pairs of electrons between atoms, resulting in the formation of a stable molecule.

Hybridization: Hybridization is the process of mixing atomic orbitals to form new hybrid orbitals, which can have different shapes and energies than the original orbitals.