Phosphorus pentachloride is a chemical compound with the formula PCl5. It is used as a reagent in various chemical reactions. It reacts vigorously with water, releasing hydrogen chloride gas.
| IUPAC Name | Phosphorus pentachloride |
| Molecular Formula | PCl5 |
| CAS Number | 10026-13-8 |
| Synonyms | Pentachlorophosphorane, Phosphorus(V) chloride, Phosphorus chloride, Phosphorus(V) chloride |
| InChI | InChI=1S/Cl5P/c1-6(2,3,4)5 |
Phosphorus Pentachloride Properties
Phosphorus Pentachloride Formula
The formula of phosphorus pentachloride is PCl5. It consists of one phosphorus atom bonded to five chlorine atoms. The formula represents the ratio of atoms in the compound.
Phosphorus Pentachloride Molar Mass
The molar mass of phosphorus(V) chloride is calculated by adding the atomic masses of all its constituent elements. Phosphorus has a molar mass of approximately 30.97 grams per mole, and each chlorine atom has a molar mass of approximately 35.45 grams per mole. Adding them together gives a molar mass of around 208.24 grams per mole for phosphorus(V) chloride.
Phosphorus Pentachloride Boiling Point
Phosphorus(V) chloride has a boiling point of approximately 167.8 degrees Celsius. At this temperature, the compound undergoes a phase change from a liquid to a gas. The boiling point is influenced by the intermolecular forces present in the compound.
Phosphorus Pentachloride Melting Point
The melting point of phosphorus(V) chloride is around -93.6 degrees Celsius. This is the temperature at which the compound transitions from a solid to a liquid state. The melting point is an important property for determining the physical behavior of the compound.
Phosphorus Pentachloride Density g/mL
The density of phosphorus(V) chloride is approximately 2.1 grams per milliliter. Density represents the mass of a substance per unit volume. The density of phosphorus(V) chloride helps in understanding its packing arrangement and the compactness of its particles.
Phosphorus Pentachloride Molecular Weight
The molecular weight of phosphorus(V) chloride is approximately 208.24 grams per mole. It is the sum of the atomic weights of all the atoms present in the compound. The molecular weight is useful in various calculations, such as determining the amount of substance in a given mass or volume.
Phosphorus Pentachloride Structure
Phosphorus(V) chloride has a molecular structure where one phosphorus atom is surrounded by five chlorine atoms. The chlorine atoms are arranged symmetrically around the central phosphorus atom, forming a trigonal bipyramidal geometry.
Phosphorus Pentachloride Solubility
Phosphorus(V) chloride is sparingly soluble in water. It reacts vigorously with water, releasing hydrogen chloride gas. However, it dissolves readily in polar solvents such as benzene and carbon tetrachloride. The solubility of phosphorus(V) chloride is influenced by the polarity and chemical properties of the solvent.
| Appearance | Colorless crystals |
| Specific Gravity | 2.1 g/mL |
| Color | Colorless |
| Odor | Pungent |
| Molar Mass | 208.24 g/mol |
| Density | 2.1 g/mL |
| Melting Point | -93.6 °C |
| Boiling Point | 167.8 °C |
| Flash Point | Not applicable |
| Water Solubility | Reacts vigorously |
| Solubility | Soluble in polar solvents such as benzene and carbon tetrachloride |
| Vapour Pressure | Not available |
| Vapour Density | Not available |
| pKa | Not available |
| pH | Not applicable |
Phosphorus Pentachloride Safety and Hazards
Phosphorus(V) chloride poses several safety hazards. It is corrosive and can cause severe burns to the skin, eyes, and respiratory system upon contact. Inhalation of its fumes or dust can lead to respiratory irritation and damage. The compound reacts violently with water, releasing toxic hydrogen chloride gas. It is also highly reactive with organic materials, potentially causing fires or explosions. Proper precautions should be taken when handling phosphorus(V) chloride, including the use of protective equipment like gloves, goggles, and a respirator. It should be stored and handled in a well-ventilated area away from incompatible substances to prevent accidents and minimize risks.
| Hazard Symbols | Corrosive |
| Safety Description | Handle with caution. Use appropriate protective equipment. |
| UN IDs | UN1806 |
| HS Code | 2812.20.00 |
| Hazard Class | 8 (Corrosive substances) |
| Packing Group | II (Moderate danger) |
| Toxicity | Toxic when ingested or inhaled. Can cause severe irritation. |
Phosphorus Pentachloride Synthesis Methods
Various methods allow the synthesis of phosphorus(V) chloride. One common method involves the reaction between phosphorus trichloride (PCl3) and chlorine gas (Cl2). In this process, the reaction vessel combines both compounds and heat or a catalyst like iron initiates the reaction. The chlorine gas acts as an oxidizing agent, converting the PCl3 into PCl5. The reaction proceeds as follows:
PCl3 + Cl2 → PCl5
Another method for synthesizing phosphorus(V) chloride involves the reaction between phosphorus and chlorine gas. This method is more direct and involves the following reaction:
P4 + 10Cl2 → 4PCl5
In this reaction, the phosphorus and chlorine gas react under suitable conditions, resulting in the formation of phosphorus(V) chloride.
It is important to note that both synthesis methods require careful handling and appropriate safety precautions. The reactions involve highly reactive and corrosive substances, so protective equipment and proper ventilation are necessary. Additionally, it is essential to carry out these reactions in a controlled environment to prevent accidents and ensure the safety of the personnel involved.
Phosphorus Pentachloride Uses
Phosphorus(V) chloride finds various applications due to its unique properties and reactivity. Here are some of its uses:
- Chemical Synthesis: Organic synthesis widely employs phosphorus(V) chloride as a reagent for converting carboxylic acids into acid chlorides and alcohols into alkyl chlorides.
- Pharmaceuticals: The synthesis of pharmaceutical compounds, including antibiotics and dyes, heavily relies on phosphorus(V) chloride as a key intermediate.
- Catalyst: Phosphorus(V) chloride catalyzes several chemical reactions, such as the Friedel-Crafts acylation and Beckmann rearrangement.
- Polymer Industry: The production of various polymers, including polyvinyl chloride (PVC) and polycarbonates, utilizes phosphorus(V) chloride as a chlorinating agent.
- Laboratory Applications: In laboratory applications, phosphorus(V) chloride acts as a drying agent to eliminate traces of water from laboratory apparatus and as a chlorinating and dehydrating agent in various reactions.
- Herbicides and Pesticides: The production of herbicides and pesticides for controlling weed growth and eliminating pests involves the use of phosphorus(V) chloride.
- Chemical Warfare Agents: Historically, phosphorus(V) chloride actively contributed to the production of chemical warfare agents, but its use for such purposes is now subject to strict regulations and restrictions.
- Metal Surface Treatment: Metal surface treatment processes utilize phosphorus(V) chloride to enhance adhesion properties and promote corrosion resistance.
- Flame Retardants: The production of flame-retardant additives for textiles, plastics, and other materials incorporates phosphorus(V) chloride.
- Pharmaceuticals Manufacturing: Phosphorus(V) chloride finds application in the production of various pharmaceuticals, including the synthesis of vitamins and hormone derivatives.
It is important to handle phosphorus(V) chloride with care and follow appropriate safety protocols due to its corrosive nature and potential health hazards.
Questions:
Q: Which is the correct formula for phosphorus pentachloride?
A: The correct formula for phosphorus(V) chloride is PCl5.
Q: What is the molecular formula for phosphorus pentachloride?
A: The molecular formula for phosphorus(V) chloride is PCl5.
Q: What mass of phosphorus pentachloride would be produced by the complete reaction of 15.2 g of P4?
A: The mass of phosphorus(V) chloride produced would be approximately 208.24 g.
Q: What is the shape of phosphorus pentachloride?
A: The shape of phosphorus(V) chloride is trigonal bipyramidal.
Q: What is the mass of a phosphorus pentachloride molecule?
A: The mass of a phosphorus(V) chloride molecule is approximately 208.24 grams per mole.
Q: Properties of phosphorus pentachloride?
A: Phosphorus(V) chloride is corrosive, reacts violently with water, and is used as a reagent in chemical synthesis.
Q: Phosphorus(V) chloride bond angles?
A: The bond angles in phosphorus pentachloride are approximately 120 degrees (between the equatorial chlorine atoms) and 90 degrees (between the axial chlorine atoms).
Q: How to make phosphorus pentachloride?
A: Phosphorus(V) chloride can be made by reacting phosphorus trichloride (PCl3) with chlorine gas (Cl2) or by direct reaction between phosphorus and chlorine gas.
Q: What is the electron geometry of the phosphorus in phosphorus pentachloride?
A: The electron geometry of phosphorus in phosphorus(V) chloride is trigonal bipyramidal.