What is n ii?

As an AI language model, I can interpret "N II" in two different contexts:

1. N II (Roman numeral notation): It represents the numeral 2 in Roman numeral notation.

2. [N II] (astronomy): It is a spectral line emitted by ionized nitrogen atoms in the visible spectrum. It appears as a bright green color and is commonly used by astronomers to study the chemical composition and properties of celestial objects such as stars, nebulae, and galaxies. The wavelength of this line is 658.4 nanometers.

If you have any other specific context in mind, feel free to provide it, and I will provide more information accordingly.