Element: Meitnerium
This element has only been produced a few atoms at a time, so most of its properties have never been measured - missing values are omitted.
General data
| Element name | Meitnerium |
|---|---|
| Chemical symbol | Mt |
| Atomic number Z | 109 |
| Year discovered | 1982 |
| Standard state (25°C) | Solid |
| Category | Transition metal |
| Block | d |
| Atomic mass | [278] |
| CPK color | #EB0026 |
Physical properties
none - only single atoms have been produced
Energy properties
none - only single atoms have been produced
Atomic structure
| Protons | 109 (Atomic number) |
|---|---|
| Neutrons (Mt-278, longest-lived isotope) | 169 |
| Electrons | 109 |
| Electron configuration | [Rn] 7s² 5f¹⁴ 6d⁷ (calculated) |
| Oxidation states | +9, +8, +6, +4, +3, +1 |
Ionization energies - NIST ASD (68 states)
| State | Charge | Ioniz. energy (eV) | Type |
|---|---|---|---|
| Mt V | 4+ | 50 ± 1.9 | calculated |
| Mt VIII | 7+ | 94 ± 2.1 | calculated |
| Mt IX | 8+ | 109 ± 2.2 | calculated |
| Mt X | 9+ | 187 ± 2.2 | calculated |
| Mt XI | 10+ | 202 ± 2.4 | calculated |
| Mt XII | 11+ | 235.9 ± 2.5 | calculated |
| Mt XIII | 12+ | 257 ± 3 | calculated |
| Mt XIV | 13+ | 289 ± 3 | calculated |
| Mt XV | 14+ | 318 ± 3 | calculated |
| Mt XVI | 15+ | 346 ± 3 | calculated |
| Mt XVII | 16+ | 386 ± 3 | calculated |
| Mt XVIII | 17+ | 406 ± 3 | calculated |
| Mt XIX | 18+ | 445 ± 3 | calculated |
| Mt XXXII | 31+ | 1035 ± 4 | calculated |
| Mt XXXIII | 32+ | 1072 ± 4 | calculated |
| Mt XXXIV | 33+ | 1112 ± 5 | calculated |
| Mt XXXV | 34+ | 1154 ± 5 | calculated |
| Mt XXXVI | 35+ | 1195 ± 5 | calculated |
| Mt XXXVII | 36+ | 1234 ± 5 | calculated |
| Mt XXXVIII | 37+ | 1311 ± 4 | calculated |
| Mt XXXIX | 38+ | 1352 ± 4 | calculated |
| Mt XL | 39+ | 1397 ± 4 | calculated |
| Mt XLI | 40+ | 1439 ± 4 | calculated |
| Mt LXIV | 63+ | 4464 ± 19 | calculated |
| Mt LXV | 64+ | 4551 ± 24 | calculated |
| Mt LXVI | 65+ | 4640 ± 30 | calculated |
| Mt LXVII | 66+ | 4740 ± 40 | calculated |
| Mt LXVIII | 67+ | 4830 ± 40 | calculated |
| Mt LXIX | 68+ | 4920 ± 50 | calculated |
| Mt LXX | 69+ | 5160 ± 50 | calculated |
| Mt LXXI | 70+ | 5250 ± 60 | calculated |
| Mt LXXII | 71+ | 5360 ± 60 | calculated |
| Mt LXXIII | 72+ | 5450 ± 70 | calculated |
| Mt LXXIV | 73+ | 5840 ± 90 | calculated |
| Mt LXXV | 74+ | 5930 ± 90 | calculated |
| Mt LXXVI | 75+ | 6030 ± 100 | calculated |
| Mt LXXVII | 76+ | 6130 ± 110 | calculated |
| Mt LXXVIII | 77+ | 7030 ± 120 | calculated |
| Mt LXXIX | 78+ | 7150 ± 120 | calculated |
| Mt LXXX | 79+ | 7430 ± 140 | calculated |
| Mt LXXXI | 80+ | 7550 ± 150 | calculated |
| Mt LXXXII | 81+ | 11460 ± 160 | calculated |
| Mt LXXXIII | 82+ | 11660 ± 170 | calculated |
| Mt LXXXIV | 83+ | 11870 ± 190 | calculated |
| Mt LXXXV | 84+ | 12100 ± 200 | calculated |
| Mt LXXXVI | 85+ | 12320 ± 220 | calculated |
| Mt LXXXVII | 86+ | 12530 ± 240 | calculated |
| Mt LXXXVIII | 87+ | 13200 ± 250 | calculated |
| Mt LXXXIX | 88+ | 13400 ± 300 | calculated |
| Mt XC | 89+ | 13700 ± 300 | calculated |
| Mt XCI | 90+ | 13900 ± 300 | calculated |
| Mt XCII | 91+ | 14500 ± 300 | calculated |
| Mt XCIII | 92+ | 14700 ± 400 | calculated |
| Mt XCIV | 93+ | 14900 ± 400 | calculated |
| Mt XCV | 94+ | 15100 ± 400 | calculated |
| Mt XCVI | 95+ | 17900 ± 400 | calculated |
| Mt XCVII | 96+ | 18200 ± 400 | calculated |
| Mt XCVIII | 97+ | 18700 ± 400 | calculated |
| Mt XCIX | 98+ | 18900 ± 500 | calculated |
| Mt C | 99+ | 36700 ± 500 | calculated |
| Mt CI | 100+ | 37200 ± 500 | calculated |
| Mt CII | 101+ | 37800 ± 500 | calculated |
| Mt CIII | 102+ | 38300 ± 500 | calculated |
| Mt CIV | 103+ | 48500 ± 500 | calculated |
| Mt CV | 104+ | 49400 ± 600 | calculated |
| Mt CVI | 105+ | 50300 ± 600 | calculated |
| Mt CVIII | 107+ | 196392 ± 14 | calculated |
| Mt CIX | 108+ | 199605 ± 15 | 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.
NIST gives no energy for some ionization stages - hence the gaps in numbering.
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