H₂, or diatomic hydrogen, is a colorless, odorless gas that consists of two hydrogen atoms bonded together. It is the simplest and most abundant molecule in the universe, playing a crucial role in various chemical reactions, including those in stars like our Sun. H₂ is often used in industrial processes, such as the production of ammonia and in fuel cells for clean energy. In its natural state, H₂ is highly flammable and must be handled with care. It can be produced through methods like electrolysis of water or natural gas reforming. As a potential energy source, H₂ is gaining attention for its role in sustainable energy solutions, particularly in reducing greenhouse gas emissions associated with fossil fuels.