molecular nitrogen
Technical term used in chemistry and related fields to refer to nitrogen in its diatomic molecular form (N₂).
Molecular nitrogen in the atmosphere cannot be used directly by plants.
窒素 is the general term for nitrogen as an element, while 分子状窒素 specifically refers to nitrogen in its molecular form (N₂).
Compound of 分子状 (molecular form) + 窒素 (nitrogen). The exact derivation is straightforward; the term is a modern scientific coinage.