Demir, known as iron in English, is a chemical element with the symbol Fe and atomic number 26. It is a metal that is abundant in the Earth's crust and is primarily used in the production of steel, which is essential for construction and manufacturing. Demir is known for its strength and durability, making it a vital material in various industries. In its pure form, demir is relatively soft and malleable, but it can be hardened through alloying and heat treatment. It is also magnetic, which makes it useful in electrical applications. Demir plays a crucial role in biological systems as well, being a key component of hemoglobin, the protein responsible for transporting oxygen in the blood.