Under normal conditions on Earth, hydrogen is not solid in nature. Hydrogen is usually found as a gas (H₂) in the atmosphere and in many compounds such as water (H₂O). Hydrogen can become a solid only at extremely low temperatures. Pure hydrogen freezes into a solid at about −259°C (14 K). So: Normal Earth conditions: Hydrogen = gas Very low temperatures (below −259°C): Hydrogen = solid In places such as very cold laboratory environments or the interiors of some planets, hydrogen may exist in solid or other unusual forms.
