No, not every molecule can exist in all four main states of matter—solid, liquid, gas, and plasma. The state of matter that a molecule can exist in depends on its chemical and physical properties, as well as the conditions of temperature and pressure.

1. Solids: In solids, molecules are closely packed and have a fixed shape and volume. The intermolecular forces are strong enough to hold the molecules in a relatively fixed position. Many molecules can form solids under appropriate conditions, such as low temperatures and high pressures. However, not all molecules have a solid state. For example, noble gases like helium or neon typically exist only as gases under normal conditions.

1. Liquids: In liquids, molecules are also close together, but they have more freedom of movement compared to solids. Liquids have a definite volume but take the shape of the container they are in. Many molecules can exist as liquids at certain temperatures and pressures. However, some molecules have a limited liquid range or do not have a liquid state under normal conditions.

1. Gases: In the gas state, molecules are far apart and have high kinetic energy. They are free to move and occupy the entire volume of the container they are in. Most molecules can exist as gases under suitable conditions, particularly at higher temperatures and lower pressures. However, some molecules have a limited gas range or may require specific conditions to exist as gases.

1. Plasma: Plasma is the fourth state of matter, characterized by high temperatures where atoms or molecules have ionized, resulting in a mixture of positively charged ions and free electrons. Plasma is commonly found in stars, lightning, and certain laboratory settings. While many substances can form a plasma state under extremely high temperatures or other energetic conditions, not all molecules can readily exist as plasmas.

The ability of a molecule to exist in different states of matter depends on its molecular structure, intermolecular forces, and the conditions of temperature and pressure. Different substances have different ranges of stability for each state, and transitions between states can occur with changes in these conditions.