Hafnium
Chemical element with atomic number 72Àdàkọ:SHORTDESC:Chemical element with atomic number 72
Hafnium, 72 Hafnium Pípè / ˈ h æ f n i ə m / (HAF -nee-əm Ìhànsójú steel grey Ìwúwo átọ̀mù A r, std (Hf) 178.486(6) [1] Hafnium ní orí tábìlì àyè
Nọ́mbà átọ̀mù (Z ) 72 Ẹgbẹ́ group 4 Àyè àyè 6 Àdìpọ̀ Àdìpọ̀-d Ẹ̀ka ẹ́límẹ́ntì Transition metalÌtò ẹ̀lẹ́ktrọ́nù [Xe ] 4f14 5d2 6s2 Iye ẹ̀lẹ́ktrọ́nù lórí ìpele kọ̀ọ̀kan 2, 8, 18, 32, 10, 2 Àwọn ohun ìní ara Ìfarahàn at STP solid Ìgbà ìyọ́ 2506 K (2233 °C, 4051 °F) Ígbà ìhó 4876 K (4603 °C, 8317 °F) Kíki (near r.t. ) 13.31 g/cm3 when liquid (at m.p. ) 12 g/cm3 Heat of fusion 27.2 kJ/mol Heat of 571 kJ/mol Molar heat capacity 25.73 J/(mol·K) pressure
P (Pa)
1
10
100
1 k
10 k
100 k
at T (K)
2689
2954
3277
3679
4194
4876
Atomic properties Oxidation states −2, +1, +2, +3, +4 Electronegativity Pauling scale: 1.3 Atomic radius empirical: 159 pm Covalent radius 175±10 pm Color lines in a spectral range Spectral lines of hafnium Other properties Natural occurrence primordial Crystal structure hexagonal Speed of sound thin rod 3010 m/s (at 20 °C) Thermal expansion 5.9 µm/(m·K) (at 25 °C) Thermal conductivity 23.0 W/(m·K) Electrical resistivity 331 n Ω·m (at 20 °C) Magnetic ordering paramagnetic[2] Young's modulus 78 GPa Shear modulus 30 GPa Bulk modulus 110 GPa Poisson ratio 0.37 Mohs hardness 5.5 Vickers hardness 1760 MPa Brinell hardness 1700 MPa CAS Number 7440-58-6 Main isotopes of hafnium
Isotope
Abundance
Half-life (t 1/2 )
Decay mode
Product
172 Hf
syn
1.87 y
ε
0.350
172 Lu
174 Hf
0.162%
2×1015 y
α
2.495
170 Yb
176 Hf
5.206%
176 Hf is stable with 104 neutrons
177 Hf
18.606%
177 Hf is stable with 105 neutrons
178 Hf
27.297%
178 Hf is stable with 106 neutrons
178m2 Hf
syn
31 y
IT
2.446
178 Hf
179 Hf
13.629%
179 Hf is stable with 107 neutrons
180 Hf
35.1%
180 Hf is stable with 108 neutrons
182 Hf
syn
9×106 y
β−
0.373
182 Ta
Àdàkọ:Category-inline
Itokasi
↑ Meija, Juris; Coplen, Tyler B.; Berglund, Michael; Brand, Willi A.; De Bièvre, Paul; Gröning, Manfred; Holden, Norman E.; Irrgeher, Johanna et al. (2016). "Atomic weights of the elements 2013 (IUPAC Technical Report)". Pure and Applied Chemistry 88 (3): 265–91. doi:10.1515/pac-2015-0305 . ↑ Magnetic susceptibility of the elements and inorganic compounds , in Handbook of Chemistry and Physics 81st edition, CRC press.
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