Element: Niobium
General data
| Element name | Niobium |
|---|---|
| Chemical symbol | Nb |
| Atomic number Z | 41 |
| Year discovered | 1801 |
| Standard state (25°C) | Solid |
| Category | Transition metal |
| Block | d |
| Atomic mass | 92.906 |
| CPK color | #73C2C9 |
Physical properties
| Melting point | 2750 K (2477 °C) |
|---|---|
| Boiling point | 5017 K (4744 °C) |
| Density | 8.57 g/cm³ |
Energy properties
| First ionization energy | 6.759 eV |
|---|---|
| Electron affinity | 0.893 eV |
Atomic structure
| Protons | 41 (Atomic number) |
|---|---|
| Neutrons (Nb-93, most abundant isotope) | 52 |
| Electrons | 41 |
| Electron configuration | [Kr] 5s¹ 4d⁴ |
| Oxidation states | +5, +3 |
| Electronegativity (Pauling) | 1.6 |
| Atomic radius (van der Waals) | 207 pm |
Ionization energies - NIST ASD (41 states)
| State | Charge | Ioniz. energy (eV) | Type |
|---|---|---|---|
| Nb I | 0+ | 6.75885 ± 0.00004 | measured |
| Nb II | 1+ | 14.32 | semi-empirical |
| Nb III | 2+ | 25.04 | semi-empirical |
| Nb IV | 3+ | 37.611 ± 0.022 | measured |
| Nb V | 4+ | 50.5728 ± 0.0025 | measured |
| Nb VI | 5+ | 102.069 ± 0.006 | semi-empirical |
| Nb VII | 6+ | 119.1 ± 0.4 | measured |
| Nb VIII | 7+ | 136 ± 2.1 | calculated |
| Nb IX | 8+ | 159.2 ± 0.7 | semi-empirical |
| Nb X | 9+ | 180 ± 2.2 | calculated |
| Nb XI | 10+ | 200.28 ± 0.06 | semi-empirical |
| Nb XII | 11+ | 246.1 ± 0.4 | semi-empirical |
| Nb XIII | 12+ | 268.59 ± 0.04 | measured |
| Nb XIV | 13+ | 482.5 ± 1.5 | semi-empirical |
| Nb XV | 14+ | 530 ± 3 | calculated |
| Nb XVI | 15+ | 581 ± 3 | calculated |
| Nb XVII | 16+ | 636 ± 3 | calculated |
| Nb XVIII | 17+ | 688 ± 3 | calculated |
| Nb XIX | 18+ | 758 ± 3 | calculated |
| Nb XX | 19+ | 816 ± 4 | calculated |
| Nb XXI | 20+ | 877 ± 4 | calculated |
| Nb XXII | 21+ | 940 ± 4 | calculated |
| Nb XXIII | 22+ | 1000 ± 4 | calculated |
| Nb XXIV | 23+ | 1176 ± 4 | semi-empirical |
| Nb XXV | 24+ | 1230.6 ± 1.3 | semi-empirical |
| Nb XXVI | 25+ | 1293.7 ± 1.8 | semi-empirical |
| Nb XXVII | 26+ | 1368 ± 5 | semi-empirical |
| Nb XXVIII | 27+ | 1439 ± 3 | semi-empirical |
| Nb XXIX | 28+ | 1488 ± 7 | semi-empirical |
| Nb XXX | 29+ | 1625.9 ± 2.3 | semi-empirical |
| Nb XXXI | 30+ | 1684.97 ± 0.05 | semi-empirical |
| Nb XXXII | 31+ | 4020.1 ± 2.2 | semi-empirical |
| Nb XXXIII | 32+ | 4187 ± 7 | semi-empirical |
| Nb XXXIV | 33+ | 4369 ± 9 | semi-empirical |
| Nb XXXV | 34+ | 4540 ± 30 | semi-empirical |
| Nb XXXVI | 35+ | 4815 ± 5 | semi-empirical |
| Nb XXXVII | 36+ | 5011 ± 4 | semi-empirical |
| Nb XXXVIII | 37+ | 5265 ± 5 | semi-empirical |
| Nb XXXIX | 38+ | 5426.066 ± 0.015 | calculated |
| Nb XL | 39+ | 22648.046 ± 0.007 | calculated |
| Nb XLI | 40+ | 23388.85 ± 0.004 | calculated |
Value type as given by NIST ASD: measured - from evaluated experimental data; calculated - from ab initio calculations (mostly highly ionised atoms that have not been measured; for the simplest ones, e.g. H I, the calculation is more accurate than measurement); semi-empirical - from interpolation, extrapolation or another semi-empirical method.
Photos
Isotopes (37)
| A | N | Half-life | Decay |
|---|---|---|---|
| Nb-81 | 40 | < 40 ns | EC/β⁺ |
| Nb-82 | 41 | 50 ms | EC/β⁺ |
| Nb-83 | 42 | 3.9 s | EC/β⁺ |
| Nb-84 | 43 | 9.8 s | EC/β⁺ |
| Nb-85 | 44 | 20.5 s | EC/β⁺ |
| Nb-86 | 45 | 88 s | EC/β⁺ |
| Nb-87 | 46 | 3.7 min | EC/β⁺ |
| Nb-88 | 47 | 14.50 min | EC/β⁺ |
| Nb-89 | 48 | 2.03 h | EC/β⁺ |
| Nb-90 | 49 | 14.60 h | EC/β⁺ |
| Nb-91 | 50 | 680 a | EC/β⁺ |
| Nb-92 | 51 | 3.47×10⁷ a | EC/β⁺ |
| Nb-93 | 52 | stable | - |
| Nb-94 | 53 | 20400 a | β⁻ |
| Nb-95 | 54 | 34.991 d | β⁻ |
| Nb-96 | 55 | 23.35 h | β⁻ |
| Nb-97 | 56 | 72.1 min | β⁻ |
| Nb-98 | 57 | 2.86 s | β⁻ |
| Nb-99 | 58 | 15.0 s | β⁻ |
| Nb-100 | 59 | 1.4 s | β⁻ |
| Nb-101 | 60 | 7.2 s | β⁻ |
| Nb-102 | 61 | 4.3 s | β⁻ |
| Nb-103 | 62 | 1.36 s | β⁻ |
| Nb-104 | 63 | 4.9 s | β⁻ |
| Nb-105 | 64 | 2.92 s | β⁻ |
| Nb-106 | 65 | 1.097 s | β⁻ |
| Nb-107 | 66 | 287 ms | β⁻ |
| Nb-108 | 67 | 194 ms | β⁻ |
| Nb-109 | 68 | 107 ms | β⁻ |
| Nb-110 | 69 | 75 ms | β⁻ |
| Nb-111 | 70 | 54 ms | β⁻ |
| Nb-112 | 71 | 38 ms | β⁻ |
| Nb-113 | 72 | 32 ms | β⁻ |
| Nb-114 | 73 | 17 ms | β⁻ |
| Nb-115 | 74 | 23 ms | β⁻ |
| Nb-116 | 75 | unknown | β⁻ |
| Nb-117 | 76 | unknown | β⁻ |
Data sources
- PubChem Periodic Table API - Retrieved on 29 June 2026 - licence: CC0
- IUPAC CIAAW - Abridged Standard Atomic Weights 2024 - Table version: 2024 - licence: Public domain
- NNDC Wallet Cards 2023 - Data as of 15 October 2024 - licence: Public domain
- NIST Atomic Spectra Database (ASD) - Retrieved on 29 June 2026 - licence: © U.S. Secretary of Commerce
- Images of Elements - Retrieved on 29 June 2026 - licence: CC BY 3.0