1. of, relating to, or containing niobium, especially in a lower valence state (typically +2 or +3)
Usage: chemistry; technical

Examples

• Niobous compounds are less common than their niobic counterparts.
• The chemist studied the properties of niobous chloride in the laboratory.
• Niobous oxide exhibits different reactivity compared to niobic oxide.
• The reduction of niobic acid can produce niobous species.