What is the Composition of Yellow Phosphorus?


The Composition of Yellow Phosphorus: A Comprehensive Guide

Introduction to Yellow Phosphorus

Yellow phosphorus, also known as white phosphorus, is a highly reactive and toxic chemical element with the symbol P and atomic number 15. It is an essential element for life, playing a crucial role in various biological processes. In this article, we will explore the composition of yellow phosphorus, its properties, and its applications in different fields.

The Molecular Structure of Yellow Phosphorus

Yellow phosphorus exists in a molecular form, consisting of tetrahedral P4 molecules. Each molecule is composed of four phosphorus atoms arranged in a pyramid shape, with one atom at the apex and the other three forming the triangular base. This unique structure gives yellow phosphorus its distinctive properties.

The Chemical Formula of Yellow Phosphorus

The chemical formula for yellow phosphorus is P4, representing the tetrahedral arrangement of four phosphorus atoms in each molecule. This formula indicates that yellow phosphorus is composed of only phosphorus atoms, unlike other forms of phosphorus such as red or black phosphorus, which have different structures.

The Physical Properties of Yellow Phosphorus

Yellow phosphorus is a waxy, translucent, and highly reactive solid with a pale yellow color. It has a low melting point of about 44 °C (111 °F) and a boiling point of approximately 280 °C (536 °F). It is insoluble in water but soluble in organic solvents. Moreover, yellow phosphorus emits a faint glow in the dark due to its high reactivity with oxygen.

The Chemical Properties of Yellow Phosphorus

Yellow phosphorus is highly reactive and readily combines with other elements. It reacts vigorously with oxygen, forming phosphorus pentoxide (P2O5), a white solid. It also reacts with halogens, such as chlorine, bromine, and iodine, to form phosphorus halides. Additionally, yellow phosphorus can undergo spontaneous combustion when exposed to air, making it extremely hazardous.

The Occurrence of Yellow Phosphorus

Yellow phosphorus does not occur naturally in its pure form. However, it is commonly found in combination with other minerals, such as phosphate rocks and bones. It is primarily obtained from phosphorite deposits, which are sedimentary rocks rich in phosphorus. The extraction process involves heating the raw materials with carbon and silica to reduce phosphates into yellow phosphorus.

The Industrial Production of Yellow Phosphorus

Yellow phosphorus is produced on an industrial scale through a process called the thermal reduction of phosphate ores. In this process, phosphate ores are first converted into elemental phosphorus by heating them with coke and silica in electric or blast furnaces. The resulting crude yellow phosphorus is then purified by fractional distillation.

The Uses of Yellow Phosphorus

Yellow phosphorus has various applications in different industries. It is primarily used in the production of phosphoric acid, which is a key ingredient in fertilizers, detergents, and food additives. It is also used in the production of matches, fireworks, incendiary devices, and smoke bombs. Furthermore, yellow phosphorus finds applications in the synthesis of organic chemicals, pharmaceuticals, and pesticides.

The Health and Environmental Hazards of Yellow Phosphorus

Yellow phosphorus is highly toxic and poses significant health hazards. Inhalation or ingestion of its fumes can cause severe respiratory and gastrointestinal problems. Prolonged exposure to yellow phosphorus can lead to chronic health issues, including liver and kidney damage. Moreover, the combustion of yellow phosphorus releases toxic gases and pollutants, contributing to environmental pollution.


In conclusion, yellow phosphorus is a highly reactive and toxic chemical element with a unique molecular structure. It is primarily composed of tetrahedral P4 molecules and has various physical and chemical properties. Despite its hazards, yellow phosphorus plays a critical role in numerous industries and biological processes. Understanding its composition and properties is essential for ensuring its safe handling and utilization.

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