| 释义 |
WordReference Random House Unabridged Dictionary of American English © 2024ni•o•bi•um (nī ō′bē əm),USA pronunciation n. [Chem.]- a steel-gray metallic element resembling tantalum in its chemical properties;
becomes a superconductor below 9 K;
used chiefly in alloy steels. Symbol: Nb;
at. no.: 41;
at. wt.: 92.906;
sp. gr.: 8.4 at 20°C.
- Neo-Latin; see Niobe, -ium
- 1835–45
Collins Concise English Dictionary © HarperCollins Publishers:: niobium /naɪˈəʊbɪəm/ n - a ductile white superconductive metallic element that occurs principally in columbite and tantalite: used in steel alloys. Symbol: Nb; atomic no: 41; atomic wt: 92.90638; valency: 2, 3, or 5; relative density: 8.57; melting pt: 2469±10°C; boiling pt: 4744°C
Former name: columbium
Etymology: 19th Century: from New Latin, from Niobe (daughter of Tantalus), so named because it occurred in tantalite |