Phosphorus oxide (P2O5) is a chemical compound. It is formed by combining two atoms of phosphorus and five atoms of oxygen.
| IUPAC name | Phosphorus pentoxide |
| Molecular formula | P2O5 |
| CAS number | 1314-56-3 |
| Synonyms | Phosphoric anhydride, Phosphorus(V) oxide, Diphosphorus pentoxide |
| InChI | InChI=1S/2O.P2/c2*1-3-2 |
Phosphorus Oxide Properties
Phosphorus Oxide Formula
The formula of diphosphorus pentoxide is P2O5. It consists of two atoms of phosphorus and five atoms of oxygen. This chemical formula represents the ratio of elements in the compound.
Phosphorus Oxide Molar Mass
The molar mass of diphosphorus pentoxide (P2O5) is calculated by adding the atomic masses of its constituent elements. Phosphorus has an atomic mass of approximately 31.0 grams per mole, while oxygen has an atomic mass of about 16.0 grams per mole. Therefore, the molar mass of P2O5 is around 141.9 grams per mole.
Phosphorus Oxide Boiling Point
Diphosphorus pentoxide does not have a specific boiling point. Instead, it undergoes a chemical reaction when heated, converting into phosphoric acid (H3PO4) and releasing heat in the process. Therefore, it does not have a well-defined boiling point like many other compounds.
Phosphorus Oxide Melting Point
Diphosphorus pentoxide (P2O5) has a melting point of approximately 340 degrees Celsius (644 degrees Fahrenheit). At this temperature, the solid compound transforms into a liquid state. It is important to note that diphosphorus pentoxide is highly hygroscopic, meaning it readily absorbs moisture from the air.
Phosphorus Oxide Density g/mL
The density of diphosphorus pentoxide is around 2.39 grams per milliliter (g/mL). Density is a measure of mass per unit volume, and this value indicates the heaviness or compactness of the substance. The density of diphosphorus pentoxide contributes to its physical properties and behavior in various applications.
Phosphorus Oxide Molecular Weight
The molecular weight of diphosphorus pentoxide (P2O5) is approximately 141.9 grams per mole. This value represents the sum of the atomic masses of phosphorus and oxygen in the compound. The molecular weight is often used in calculations involving chemical reactions and the stoichiometry of compounds.
Phosphorus Oxide Structure
Diphosphorus pentoxide has a molecular structure consisting of two phosphorus atoms bonded to five oxygen atoms. The arrangement of atoms forms a cyclic structure, with each phosphorus atom bonded to two oxygen atoms and sharing a double bond with the neighboring phosphorus atom.
Phosphorus Oxide Solubility
Diphosphorus pentoxide is not soluble in water. It reacts vigorously with water to form phosphoric acid, releasing heat in the process. However, it is soluble in some organic solvents such as carbon disulfide and chloroform. The solubility characteristics of diphosphorus pentoxide play a role in its chemical reactivity and applications.
| Appearance | White crystalline solid |
| Specific Gravity | 2.39 g/mL |
| Color | Colorless |
| Odor | Odorless |
| Molar Mass | 141.9 g/mol |
| Density | 2.39 g/mL |
| Melting Point | 340°C (644°F) |
| Boiling Point | Reacts to form phosphoric acid |
| Flash Point | Not applicable |
| Water Solubility | Reacts with water to form phosphoric acid |
| Solubility | Soluble in organic solvents such as carbon disulfide, chloroform |
| Vapor Pressure | Not applicable |
| Vapor Density | Not applicable |
| pKa | Not applicable |
| pH | Not applicable |
Phosphorus Oxide Safety and Hazards
Diphosphorus pentoxide (P2O5) poses certain safety hazards and precautions should be taken when handling it. It reacts violently with water, releasing heat and forming phosphoric acid, which can cause burns and irritation to the skin, eyes, and respiratory system. It is important to avoid contact with the substance and use appropriate protective equipment, such as gloves, goggles, and a respirator, when working with diphosphorus pentoxide. Additionally, it is crucial to store the compound in a tightly sealed container away from moisture and incompatible materials. Proper ventilation should be ensured to prevent the accumulation of vapors.
| Hazard Symbols | Corrosive, Harmful |
| Safety Description | – Causes severe skin burns and eye damage – May be harmful if swallowed or inhaled – Reacts violently with water – Keep away from moisture and incompatible materials |
| UN IDs | UN 1807 |
| HS Code | 2819.10.90 |
| Hazard Class | Class 8 (Corrosive substances) |
| Packing Group | PG II (Medium danger) |
| Toxicity | Toxic to aquatic life, may cause long-term adverse effects in the aquatic environment |
Phosphorus Oxide Synthesis Methods
Various methods can synthesize diphosphorus pentoxide (P2O5).
One common method involves the combustion of phosphorus in the presence of excess oxygen. This reaction produces phosphorus pentoxide as a white solid residue. The equation for this process is P4 + 5O2 → 2P2O5.
Another method involves the controlled oxidation of phosphorus compounds, such as phosphorus trichloride (PCl3) or phosphorus tribromide (PBr3), using oxygen or air. The reaction typically takes place at elevated temperatures, and the resulting product is phosphorus pentoxide.
In order to obtain diphosphorus pentoxide, one can dehydrate phosphoric acid (H3PO4) by heating it to high temperatures. This process removes water molecules and results in the formation of phosphorus pentoxide.
Another method to prepare diphosphorus pentoxide involves the thermal decomposition of certain phosphate salts. For example, heating ammonium dihydrogen phosphate (NH4H2PO4) or ammonium phosphate ((NH4)3PO4) leads to the formation of phosphorus pentoxide.
When synthesizing diphosphorus pentoxide, it is crucial to exercise caution due to its reactivity and the generation of heat during specific reactions. One should adhere to proper safety measures, such as working in a well-ventilated area and wearing appropriate protective equipment.
These synthesis methods offer pathways to acquire diphosphorus pentoxide, which finds applications in various fields, including the production of phosphoric acid, fertilizers, and chemical intermediates.
Phosphorus Oxide Uses
Diphosphorus pentoxide (P2O5) finds diverse applications across several industries due to its unique properties. Here are some common uses of diphosphorus pentoxide:
- Production of Phosphoric Acid: The manufacturing of phosphoric acid extensively uses diphosphorus pentoxide as a key precursor. Phosphoric acid finds wide application in fertilizers, food additives, and cleaning agents.
- Manufacturing of Fertilizers: Diphosphorus pentoxide plays a vital role in producing various phosphate-based fertilizers, including superphosphate and ammonium phosphate fertilizers. These fertilizers provide plants with essential nutrients for promoting healthy growth.
- Chemical Intermediates: The synthesis of various organic compounds, such as pharmaceuticals, pesticides, and flame retardants, relies on diphosphorus pentoxide as a chemical intermediate.
- Dehydrating Agent: Diphosphorus pentoxide exhibits a strong affinity for water and acts as a dehydrating agent. It finds usage in several chemical reactions to eliminate water and drive the desired reactions forward.
- Catalyst: Diphosphorus pentoxide acts as a catalyst in specific chemical reactions. It facilitates these reactions by reducing the activation energy and thereby increasing the reaction rates.
- Desiccant: The hygroscopic nature of diphosphorus pentoxide makes it suitable for use as a desiccant in moisture-sensitive applications. It effectively absorbs and eliminates moisture from the surroundings.
- Glass Manufacturing: Glass formulations incorporate diphosphorus pentoxide to modify their properties, including thermal expansion and refractive index. Specialized glasses, such as optical glasses and borosilicate glasses, actively employ it.
- Metal Surface Treatment: Metal surface treatments, such as phosphating, utilize diphosphorus pentoxide to enhance corrosion resistance and improve paint adhesion on metal surfaces.
These various applications highlight the significance of diphosphorus pentoxide in industries ranging from agriculture to pharmaceuticals, making it a valuable compound with broad utility.
Questions:
Q: What is the oxidation number of phosphorus in the PO ion?
A: The oxidation number of phosphorus in the PO ion is +5.
Q: What is the oxidation state of an individual phosphorus atom in PO43−?
A: The oxidation state of an individual phosphorus atom in PO43− is +5.
Q: What is the oxidation number for phosphorus?
A: The oxidation number for phosphorus can vary, but it commonly appears as +3 or +5.
Q: What is the name of the compound P2O5?
A: The name of the compound P2O5 is phosphorus(V) pentoxide.
Q: What is P2O5?
A: P2O5 is a chemical compound called phosphorus(V) pentoxide.
Q: Which is the correct name for P2O5?
A: The correct name for P2O5 is phosphorus(V) pentoxide.
Q: What is the name for P2O5?
A: The name for P2O5 is phosphorus(V) pentoxide.
Q: Is P2O5 amphoteric?
A: No, P2O5 is not amphoteric. It is an acidic oxide.
Q: What is P2O5 fertilizer?
A: P2O5 fertilizer refers to fertilizers that contain phosphorus(V) pentoxide (P2O5) as a source of phosphorus, which is important for plant growth.
Q: Is P2O5 acidic or basic?
A: P2O5 is an acidic compound.
Q: Is P2O5 an ionic compound?
A: No, P2O5 is a covalent compound.
Q: How to calculate P2O5 in fertilizer?
A: To calculate the amount of P2O5 in a fertilizer, multiply the percentage of P2O5 by the weight of the fertilizer.
Q: P2O5 properties, soluble?
A: P2O5 is sparingly soluble in water but readily reacts with water to form phosphoric acid.
Q: How many kilograms P in 14% P2O5?
A: To calculate the amount of phosphorus (P) in 14% P2O5, multiply the weight of the fertilizer by 0.14.