Hafnium-178

Properties and data of the isotope ¹⁷⁸Hf.

Contents

See also: List of individual Hafnium isotopes (and general data sources).

General data

Name of the isotope:Hafnium-178; Hf-178Symbol:¹⁷⁸Hf or 17872HfMass number A:178 (= number of nucleons)Atomic number Z:72 (= number of protons)Neutrons N:106Nucleon pairing (Z - N):even - evenNuclear ratio (N/Z ratio):1.4722222222222 (= neutron-proton ratio)Neutron excess (N-Z):34Isotopic mass:177.94371(2) u (atomic weight of Hafnium-178)Nuclide mass:177.904216 u (calculated nuclear mass without electrons)Mass excess:-52.4338 MeVMass defect:1.5381734 u (per nucleus)Nuclear binding energy:1432.79929306 MeV (per nucleus)
8.04943423 MeV (average binding energy per nucleon)Separation energy:S_N = 7.62594(18) MeV (first neutron)
S_P = 7.3404(8) MeV (first proton)Half-life:stableSpin and parity:
(nuclear angular momentum)0+Charge radius:5.3371(31) femtometer fmYear of discovery:1934

Parent Nuclides

Direct parent isotopes are: ¹⁷⁸Ta, ¹⁷⁸Lu.

Occurrence

Comparison of the natural Hafnium isotopes including isotopic abundance (mole fraction of the isotope mixture in percent):

	Atomic Mass m_a	Quantity	Half-life	Spin
Hafnium Isotopic mixture	178.486 u	100 %
Isotope ¹⁷⁴Hf	173.94005(2) u	0.16(12) %	2.0(4) × 10¹⁵ years	0+
Isotope ¹⁷⁶Hf	175.94141(2) u	5.26(70) %	stable	0+
Isotope ¹⁷⁷Hf	176.94323(2) u	18.60(16) %	stable	7/2-
Isotope ¹⁷⁸Hf	177.94371(2) u	27.28(28) %	stable	0+
Isotope ¹⁷⁹Hf	178.94582(2) u	13.62(11) %	stable	9/2+
Isotope ¹⁸⁰Hf	179.94656(2) u	35.08(33) %	stable	0+

Nuclear Isomers

Nuclear isomers or excited states with the activation energy in keV related to the ground state.

Nuclear Isomer	Excitation Energy	Half-life	Spin
^178m1Hf	1147.416(6) keV	4.0(2) s	8-
^178m2Hf	2446.09(8)	31(1) years	16+

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 106) and isobaric (same nucleon number A = 178) with Hafnium-178. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 106	Isobar A = 178
64	¹⁷⁰Gd
65	¹⁷¹Tb
66	¹⁷²Dy
67	¹⁷³Ho
68	¹⁷⁴Er
69	¹⁷⁵Tm	¹⁷⁸Tm
70	¹⁷⁶Yb	¹⁷⁸Yb
71	¹⁷⁷Lu	¹⁷⁸Lu
72	¹⁷⁸Hf	¹⁷⁸Hf
73	¹⁷⁹Ta	¹⁷⁸Ta
74	¹⁸⁰W	¹⁷⁸W
75	¹⁸¹Re	¹⁷⁸Re
76	¹⁸²Os	¹⁷⁸Os
77	¹⁸³Ir	¹⁷⁸Ir
78	¹⁸⁴Pt	¹⁷⁸Pt
79	¹⁸⁵Au	¹⁷⁸Au
80	¹⁸⁶Hg	¹⁷⁸Hg
81	¹⁸⁷Tl	¹⁷⁸Tl
82	¹⁸⁸Pb	¹⁷⁸Pb
83	¹⁸⁹Bi
84	¹⁹⁰Po
85	¹⁹¹At