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Element: Hafnium

General data

Element nameHafnium
Chemical symbolHf
Atomic number Z72
Year discovered1923
Standard state (25°C)Solid
CategoryTransition metal
Blockd
Atomic mass178.49
CPK color#4DC2FF

Physical properties

Melting point2506 K (2233 °C)
Boiling point4876 K (4603 °C)
Density13.3 g/cm³

Energy properties

First ionization energy6.825 eV
Electron affinityno data

Atomic structure

Protons72 (Atomic number)
Neutrons (Hf-180, most abundant isotope)108
Electrons72
Electron configuration[Xe] 6s² 4f¹⁴ 5d²
Oxidation states+4
Electronegativity (Pauling)1.3
Atomic radius (van der Waals)212 pm

Ionization energies - NIST ASD (72 states)

StateChargeIoniz. energy (eV)Type
Hf I0+6.82507 ± 0.000012measured
Hf II1+14.61 ± 0.04calculated
Hf III2+22.55 ± 0.04calculated
Hf IV3+33.37 ± 0.025semi-empirical
Hf V4+68.37 ± 0.04semi-empirical
Hf VI5+98 ± 5calculated
Hf VII6+118 ± 6calculated
Hf VIII7+137 ± 7calculated
Hf IX8+157 ± 8calculated
Hf X9+187 ± 9calculated
Hf XI10+209 ± 10calculated
Hf XII11+230 ± 12calculated
Hf XIII12+270 ± 14calculated
Hf XIV13+310 ± 15calculated
Hf XV14+334 ± 16calculated
Hf XVI15+359 ± 17calculated
Hf XVII16+399 ± 20calculated
Hf XVIII17+440 ± 22calculated
Hf XIX18+481 ± 24calculated
Hf XX19+520 ± 30calculated
Hf XXI20+570 ± 30calculated
Hf XXII21+610 ± 30calculated
Hf XXIII22+650 ± 30calculated
Hf XXIV23+690 ± 30calculated
Hf XXV24+730 ± 40calculated
Hf XXVI25+772 ± 9calculated
Hf XXVII26+1002 ± 4calculated
Hf XXVIII27+1047 ± 4calculated
Hf XXIX28+1094 ± 4calculated
Hf XXX29+1146 ± 4calculated
Hf XXXI30+1195 ± 4calculated
Hf XXXII31+1245 ± 4calculated
Hf XXXIII32+1311 ± 4calculated
Hf XXXIV33+1362 ± 5calculated
Hf XXXV34+1417 ± 5calculated
Hf XXXVI35+1467 ± 5calculated
Hf XXXVII36+1669 ± 5calculated
Hf XXXVIII37+1719 ± 4calculated
Hf XXXIX38+1776 ± 4calculated
Hf XL39+1827 ± 4calculated
Hf XLI40+1963 ± 4calculated
Hf XLII41+2022 ± 4calculated
Hf XLIII42+2159 ± 4calculated
Hf XLIV43+2218.9 ± 1.1semi-empirical
Hf XLV44+3741 ± 4calculated
Hf XLVI45+3858 ± 4calculated
Hf XLVII46+3984 ± 4calculated
Hf XLVIII47+4118 ± 4calculated
Hf XLIX48+4246 ± 4calculated
Hf L49+4372 ± 4calculated
Hf LI50+4573 ± 4calculated
Hf LII51+4703 ± 4calculated
Hf LIII52+4846 ± 4calculated
Hf LIV53+4980 ± 5calculated
Hf LV54+5350 ± 5calculated
Hf LVI55+5468 ± 5calculated
Hf LVII56+5595 ± 5calculated
Hf LVIII57+5713 ± 6calculated
Hf LIX58+6149 ± 6calculated
Hf LX59+6284 ± 7calculated
Hf LXI60+6545 ± 10calculated
Hf LXII61+6674 ± 12calculated
Hf LXIII62+14678 ± 15calculated
Hf LXIV63+14999 ± 19calculated
Hf LXV64+15351 ± 24calculated
Hf LXVI65+15680 ± 30calculated
Hf LXVII66+17280 ± 40calculated
Hf LXVIII67+17680 ± 40calculated
Hf LXIX68+18180 ± 50calculated
Hf LXX69+18502.32 ± 0.17calculated
Hf LXXI70+74565.91 ± 0.16calculated
Hf LXXII71+76077.7 ± 0.11calculated

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

Photo of the element: Hafnium (Hf)
© images-of-elements.com (CC BY 3.0)

Isotopes (38)

ANHalf-lifeDecay
Hf-15381> 60 nsEC/β⁺
Hf-154822 sEC/β⁺
Hf-15583840 msEC/β⁺
Hf-1568423 msα
Hf-15785115 msα
Hf-158862.9 sα
Hf-159875.2 sEC/β⁺
Hf-1608813.6 sEC/β⁺
Hf-1618918.4 sEC/β⁺
Hf-1629038.7 sEC/β⁺
Hf-1639140.0 sEC/β⁺
Hf-16492111 sEC/β⁺
Hf-1659376 sEC/β⁺
Hf-166946.8 minEC/β⁺
Hf-167952.05 minEC/β⁺
Hf-1689625.95 minEC/β⁺
Hf-169973.25 minEC/β⁺
Hf-1709816.01 hEC
Hf-1719912.1 hEC/β⁺
Hf-1721001.87 aEC
Hf-17310123.6 hEC/β⁺
Hf-1741027.0×10¹⁶ aα
Hf-17510370.67 dEC
Hf-176104stable-
Hf-177105stable-
Hf-178106stable-
Hf-179107stable-
Hf-180108stable-
Hf-18110942.39 dβ⁻
Hf-1821108.90×10⁶ aβ⁻
Hf-1831111.019 hβ⁻
Hf-1841124.12 hβ⁻
Hf-1851133.5 minβ⁻
Hf-1861142.6 minβ⁻
Hf-187115unknownβ⁻
Hf-188116unknownβ⁻
Hf-189117unknownβ⁻
Hf-190118unknownβ⁻

Data sources

More about the data sources