Chem Explorers

Phosphorus Pentafluoride: Properties Uses and Hazards Revealed

Phosphorus Pentafluoride: Properties,

Uses, and

HazardsPhosphorus pentafluoride is a compound composed of phosphorus and five fluorine atoms. It is a colorless, non-flammable, and highly toxic gas.

This article aims to provide a detailed overview of the properties, uses, and hazards associated with phosphorus pentafluoride.

Halogen Atoms and Bonds

Phosphorus pentafluoride has a covalent bond of five phosphorus-fluorine atoms, which makes it an excellent source of fluoride ions. This compound can readily donate a fluoride ion, making it an ideal reagent for many chemical reactions.

Carcinogenic Nature

Phosphorus pentafluoride is a highly toxic compound that has a toxicological effect on the environment and human health. Workers who come into contact with this compound are at risk of developing respiratory problems, skin irritation, and even death.

Melting and Boiling Point

Phosphorus pentafluoride has a melting point of -93 degrees Celsius (-135 degrees Fahrenheit) and a boiling point of -84 degrees Celsius (-119 degrees Fahrenheit), which makes it a highly volatile compound.

Acidic Character

Phosphorus pentafluoride is an acid-forming compound that creates an acidic solution when reacted with water. It can donate hydrogen ions to form a stable acid.

IUPAC Name and Chemical Formula

Phosphorus pentafluoride’s IUPAC name is phosphorus(V) fluoride. Its chemical formula is P F 5.

This compound has five fluorine atoms bonded with phosphorus.


Phosphorus pentafluoride has several applications in the industries. It is commonly used as a fluorinating agent in organic chemistry, as it can substitute a halogen atom with a fluorine atom.

This process is known as fluorination and has been used in the production of certain plastics, rubber, and pharmaceuticals. Phosphorus pentafluoride is also used in the semiconductor industry.

It is used to manufacture plasma etching gases and chemicals which are used to purify silicon wafers before they are used in electronic devices such as microprocessors.


Phosphorus pentafluoride is a highly toxic and dangerous gas. It is classified as hazardous and should only be handled by trained professionals wearing personal protective equipment (PPE).

This compound is highly reactive and can ignite when exposed to heat or an open flame. Phosphorus pentafluoride is also corrosive and can cause skin and eye irritation when exposed to humans.

Inhalation of this gas may cause respiratory problems, and in severe cases, it may even result in death.


Phosphorus pentafluoride is a highly reactive compound with several applications in the industries such as organic chemistry and semiconductor manufacturing. However, despite its widespread use, it is a highly toxic and dangerous compound.

Proper handling and storage should be observed at all times, and only well-trained professionals should handle this compound. The hazards associated with this compound should be taken seriously to avoid accidents and fatalities.

Chemical Properties

Phosphorus pentafluoride is a colorless gas with an unpleasant odor. It is highly toxic, carcinogenic, and non-flammable.

The bond between phosphorus and fluorine in this compound is an unequal bond, making it polarized, and the molecules have a net dipole moment. This feature explains why phosphorus pentafluoride has a higher boiling point than the similar-sized molecules that are completely non-polar, such as nitrogen and carbon dioxide.

Physical Properties

Phosphorus pentafluoride is a colorless gas with a musty odor. Its density is 5.57 grams per cubic centimeter, the boiling point is -84.2 degrees Celsius, and the freezing point is -93.8 degrees Celsius.

It is poorly soluble in water and other polar solvents. These properties can present handling challenges and safety risks.

The health hazards of phosphorus pentafluoride stem from its inhalation and skin and eye contact. The compound can be particularly harmful to the nervous system, respiratory organs, skin, eyes, and mucous membranes.

If an accident happens that exposes workers to phosphorus pentafluoride’s toxic fumes or liquid, they should seek medical attention immediately. The unequal bond length in phosphorus pentafluoride molecules results from the different sizes of phosphorus and fluorine atoms, which creates a partial positive charge on phosphorus and a partial negative charge on the fluorine atoms.

The molecule’s polarity explains its interaction with other charged or partially charged molecules, which are essential for its use as a reagent in many chemical reactions.


Phosphorus pentafluoride has an acidic character, which means that it readily reacts with water. When it reacts with water, it releases hydrogen fluoride gas, which is a toxic and dangerous compound.

The hydrolysis reaction of phosphorus pentafluoride can be summarized as follows:

PF5 + 4H2O H3PO4 + 5HF

The hydrolysis reaction of phosphorus pentafluoride generates a comparatively strong acid, hydrogen fluoride gas. Therefore, it is essential to handle the compound with care.

Chemical Classification

Phosphorus pentafluoride is a halide molecule comprised of phosphorus and five fluorine atoms. Its chemical formula is PF5, and it is an important fluorinating agent.

The compound is a member of a broader group of organophosphorus compounds used in various applications, including flame retardants, pesticides, hydraulic fluids, and solvents. Phosphorus pentafluoride is highly toxic and harmful, and it must be treated with caution and respect.

Its toxic fumes and gases harm both humans and the environment. This compound is sometimes seen as an alternative to other halogenating agents, such as chlorine and bromine, which are responsible for the destruction of Earth’s ozone layer.


Phosphorus pentafluoride is a compound with a range of uses, but it presents many dangers. It is classified as toxic and harmful, and should be handled by certified professionals.

Its physical and chemical properties reveal a compound that reacts unpredictably and can cause severe harm to individuals who come into contact with it. Its acute effects on the respiratory, nervous, and digestive systems, as well as the potential for long-term harm, demonstrate the importance of ensuring workplace safety when handling this compound.

Researchers, industry professionals, and policymakers must take steps to minimize the risks of exposure to phosphorus pentafluoride and similar compounds in the future.

Molecular Properties

Molar Mass, Color, Viscosity, Molar Density

Phosphorus pentafluoride has a molar mass of 125.97 grams per mole (g/mol). It is a colorless gas with a viscosity that is slightly higher than air.

Its molar density is 8.28 grams per liter (g/L), which is significantly higher than the density of air at standard temperature and pressure. The high molar mass and molar density of phosphorus pentafluoride contribute to its preference as a fluorinating agent in many applications.

For example, the high density allows it to easily displace other compounds and reagents in chemical reactions.

Melting and Boiling Point

Phosphorus pentafluoride is a gas at room temperature and atmospheric pressure, making it have no melting point and boiling point. This compound is in a gaseous state even at very low temperatures and pressures, which is due to weak intermolecular forces.

Even under high pressure and low temperature, the attractive forces between the molecules are much weaker than the energy required to overcome them. As a gas, phosphorus pentafluoride can react comparatively rapidly with other compounds, which contributes to its usefulness as a reagent.

When used in certain kinds of chemical reactions, its fast reactivity enables the reaction to proceed at a higher rate. State, Ionic Bond, and Covalent Radius

Phosphorus pentafluoride is a gaseous state compound that has an ionic bond between phosphorus (P) and fluorine (F) and a covalent radius of 140 picometers (pm).

The ionic bond is created by the transfer of an electron from phosphorus to fluorine, resulting in the formation of positively charged phosphorus and negatively charged fluorine ion. The covalent radius is attributed to the length of the covalent bond between P and F atoms in the molecule.

The bond is a single bond, and the phosphorus atom has one electron pair and five valence electrons in its outermost shell.

Electron Configuration,

Oxidation State, and


Electron Configuration

Phosphorus pentafluoride has an electron configuration of [Ne] 3s22d102p3, which shows that the phosphorus atom has five valence electrons in the 3p orbital. Out of the five valence electrons, there are three singly occupied 3p orbitals and two electrons paired in one of the orbitals.

These unpaired electrons are involved in bonding with the fluorine atoms, which results in phosphorus pentafluoride’s unique physical and chemical properties.

Oxidation State

Phosphorus pentafluoride has a pentavalent oxidation state, meaning that the phosphorus atom has a charge of +5. In this state, the phosphorus atom has lost five electrons.

Phosphorus pentafluoride oxidizes compounds by taking on an electron from the substrate. After reduction, phosphorus pentafluoride takes on the oxidation state of +3.


Phosphorus pentafluoride is an acidic compound that readily donates hydrogen ions in solution due to its Lewis acid character. The acidity is attributed to the ability of the phosphorus atom to accept lone pairs of electrons from Lewis bases in an electron donation process (Lewis acid-base reaction).

The d orbitals of phosphorus pentafluoride also contribute to its acidic properties. These orbitals facilitate the formation of dative covalent bonds, commonly referred to as coordinate covalent bonds, with Lewis bases.

The lone pairs of electrons from the Lewis bases’ atoms can be transferred to the phosphorus d orbital, making a new bond. This interaction delivers the a hydrogen ion from the phosphorus pentafluoride to the Lewis base, resulting in the acidity of the compound.

Phosphorus pentafluoride is also paramagnetic due to its unpaired electrons, meaning that it is attracted to external magnetic fields. The diamagnetic characteristics of molecules are attributed to the electron-pairing in all the orbitals of the molecule.

It is also important to note that phosphorus pentafluoride can bind to hydroxide ions, forming fluorophosphate anions that are basic.


Phosphorus pentafluoride is a unique compound with complex molecular properties. It has a high molar mass, a gaseous state with an ionic bond, and a covalent radius.

Additionally, it has a pentavalent oxidation state, an acidic character, and can form dative covalent bonds. Understanding phosphorus pentafluoride’s properties helps researchers and professionals use it more efficiently and safely while minimizing the risks to the environment and human health.

Additional Properties and Reactions

Odor, Hydrates, and Crystal Structure

Phosphorus pentafluoride has a musty and sulfur-like odor, which can be easily detected at low concentrations. The compound does not form hydrates because the hydration energies of the F- and P+ ions are so high and incompatible with each other.

The absence of hydrates and high electronegativity contribute to the low solubility of phosphorus pentafluoride in polar solvents. Nonetheless, it can interact with some proton donors such as ammonia to form adducts.

Phosphorus pentafluoride’s crystal structure belongs to the triclinic space group P1. The F-P-F bond angle is 120 degrees, while the P-F bond distance ranges between 154.17 to 155.65 picometers.

Polarity and Conductivity

The phosphorus pentafluoride molecule has a trigonal bipyramidal shape in the gas phase, with a net dipole moment of 1.03 Debye. It is a polar molecule since the five P-F bonds form a trigonal bipyramidal arrangement, with the three equatorial F atoms arranged in a plane that makes an angle of 120 degrees from each other.

The two axial F atoms are positioned perpendicular to the equatorial plane, which provides the molecule with its overall dipole moment. Phosphorus pentafluoride conduction mechanism primarily depends on its dissociation into ions, which can contribute to its conductivity.

When ionized by an external energy source such as UV light, phosphorus pentafluoride can generate free electrons that can interact with charged particles in the surroundings. The high ionization potential of the compound accounts for its low electrical conductivity under normal conditions as it requires considerable thermal or electrical energy to ionize the molecule.

Reactions with Acid, Base, Oxide, and Metal

Phosphorus pentafluoride reactions with acids, bases, oxides, and metals depend on its Lewis acid or donor features. It acts as a Lewis acid in acid-base reactions, accepting lone pairs of the Lewis base to form adducts that later react with other reagents.

For instance, when phosphorus pentafluoride is added to an acid, it forms a salt through proton transfer, which can subsequently generate the fluoride ion and the conjugate base. Phosphorus pentafluoride can form adducts with strong Lewis bases such as ammonia, leading to the formation of PF5 x 4NH3.

With metal compounds such as tungsten, it forms an adduct as WPF7. The compound’s Lewis acid character is also evident in its oxide reaction, where it can form PF3O.

This compound hydrolyzes quickly to give phosphorus oxyfluoride, PF3O2, and HF. In reactions with metals, phosphorus pentafluoride can form metal-P bonds through redox reactions with transition metals.

For example, the reaction with iron tricarbonyl gives neutral Fe(PF5)3, iron-P bonds through -backbonding. In general, transition metals can treat phosphorus pentafluoride as Lewis bases as well, leading to the formation of transition metal fluorides.


Phosphorus pentafluoride’s additional properties and reactions play essential roles in understanding its behavior in various applications. The compound has a musty odor, cannot form hydrates, and adopts a triclinic crystal structure.

It is also a polar molecule with a dipole moment and low electrical conductivity but can conduct electricity once dissociated into ions. Phosphorus pentafluoride’s Lewis acid or donor character makes it interact with acid, base, oxide, and metal compounds through proton transfer, adduct formation, and metal-P bonds.

As the compound has a range of applications, understanding these properties and reactions aids in using phosphorus pentafluoride efficiently and safely. Phosphorus pentafluoride is a compound with diverse properties and reactions that make it significant in various industries.

Its toxic nature, acidic character, and ability to form adducts and metal-P bonds highlight the compound’s importance. Understanding its molecular properties, electron configuration, and reactivity is crucial for safe handling and efficient utilization.

Phosphorus pentafluoride’s unique features, such as high molar density and polarity, contribute to its usefulness as a fluorinating agent, while its hazards necessitate proper precautions. Overall, this compound’s study enables researchers and professionals to harness its potential while safeguarding against risks, ensuring responsible and effective application.


1. Is phosphorus pentafluoride dangerous to handle?

Yes, phosphorus pentafluoride is highly toxic and must be handled with care by trained professionals wearing personal protective equipment. 2.

What are the main uses of phosphorus pentafluoride? Phosphorus pentafluoride is commonly used as a fluorinating agent in organic chemistry and semiconductor manufacturing processes.

3. What are the physical properties of phosphorus pentafluoride?

Phosphorus pentafluoride is a colorless gas with an unpleasant odor, and it has a relatively high viscosity and density compared to air. 4.

How does phosphorus pentafluoride react with acids and bases? It acts as a Lewis acid and can form adducts with bases in acid-base reactions.

It can also react with acids to form salts through proton transfer. 5.

Is phosphorus pentafluoride corrosive to human skin? Yes, phosphorus pentafluoride is corrosive and can cause skin and eye irritation.

Inhalation of its toxic fumes may lead to respiratory problems. 6.

What is the crystal structure of phosphorus pentafluoride? Phosphorus pentafluoride adopts a triclinic crystal structure, with a trigonal bipyramidal shape in the gas phase.

7. Can phosphorus pentafluoride conduct electricity?

Phosphorus pentafluoride has low electrical conductivity in its molecular state but can conduct electricity when dissociated into ions, such as under UV light. Remember to always handle phosphorus pentafluoride safely and adhere to proper handling guidelines to prevent accidents and protect human health and the environment.

Popular Posts