Hafnium-175

Properties and data of the isotope ¹⁷⁵Hf.

Contents

General Data

Radioactive Decay

Parent Nuclides

Isotones und Isobares

Literature

Hafnium-175 is a radioisotope of the chemical element hafnium, which has 103 neutrons in its atomic nucleus in addition to the element-specific 72 protons; the sum of the number of these atomic nucleus building blocks results in a mass number of 175.

A report on the discovery of the radioactive nuclide appeared in 1949 [1]: according to it, hafnium-175 was observed and identified upon irradiation of a Lutetium oxide sample with deuterons (19 MeV, hydrogen-2 nuclei) and protons (10 MeV).

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

General data

Name of the isotope:Hafnium-175; Hf-175Symbol:¹⁷⁵Hf or 17572HfMass number A:175 (= number of nucleons)Atomic number Z:72 (= number of protons)Neutrons N:103Nucleon pairing (Z - N):even - oddNuclear ratio (N/Z ratio):1.4305555555556 (= neutron-proton ratio)Neutron excess (N-Z):31Isotopic mass:174.9415115(25) u (atomic weight of Hafnium-175)Nuclide mass:174.9020175 u (calculated nuclear mass without electrons)Mass excess:-54.48169 MeVMass defect:1.514377152 u (per nucleus)Nuclear binding energy:1410.63323083 MeV (per nucleus)
8.06076132 MeV (average binding energy per nucleon)Separation energy:S_N = 6.7085(4) MeV (first neutron)
S_P = 6.2004(22) MeV (first proton)Half-life:69.90(7) dDecay constant λ:1.147716282122 × 10^-7 s^-1Specific activity α:3.950868461248 × 10⁺¹⁴ Bq g^-1
10678.02286824 Ci g^-1Spin and parity:
(nuclear angular momentum)5/2-Magnetic dipole moment:μ(μ_N) = - 0.539(32)Quadrupole moment Q:+2.72(2) barn (100 fm²)Nuclear g-factor:g_l = -0.2156Charge radius:5.3191(36) femtometer fmYear of discovery:1949

Radioactive Decay

Half-life T_½ = 69.90(7) d respectively 6.039360 × 10⁶ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
EC	¹⁷⁵Lu	100 %	0.6839(26) MeV

Parent Nuclides

Direct parent isotope is: ¹⁷⁵Ta.

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 103) and isobaric (same nucleon number A = 175) with Hafnium-175. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 103	Isobar A = 175
60	¹⁶³Nd
62	¹⁶⁵Sm
63	¹⁶⁶Eu
64	¹⁶⁷Gd
65	¹⁶⁸Tb	¹⁷⁵Tb
66	¹⁶⁹Dy
67	¹⁷⁰Ho	¹⁷⁵Ho
68	¹⁷¹Er	¹⁷⁵Er
69	¹⁷²Tm	¹⁷⁵Tm
70	¹⁷³Yb	¹⁷⁵Yb
71	¹⁷⁴Lu	¹⁷⁵Lu
72	¹⁷⁵Hf	¹⁷⁵Hf
73	¹⁷⁶Ta	¹⁷⁵Ta
74	¹⁷⁷W	¹⁷⁵W
75	¹⁷⁸Re	¹⁷⁵Re
76	¹⁷⁹Os	¹⁷⁵Os
77	¹⁸⁰Ir	¹⁷⁵Ir
78	¹⁸¹Pt	¹⁷⁵Pt
79	¹⁸²Au	¹⁷⁵Au
80	¹⁸³Hg	¹⁷⁵Hg
81	¹⁸⁴Tl
82	¹⁸⁵Pb
83	¹⁸⁶Bi
84	¹⁸⁷Po
85	¹⁸⁸At

Data changes (history)

Half-life: The value t_1/2 = 69.90 ± 0.07 days, published in 2025, was adopted here [3]! Older values: Originally 70 ± 2 days [1]; 70.65 ± 0.19 days ([2] and AME2020).

External data and identifiers

Adopted Levels, Gammas:NuDat 175Hf

Literature and References

[1] - Geoffrey Wilkinson, Harry G. Hicks:
Hf¹⁷⁵, a New Radioactive Isotope of Hafnium.
In: Physical Review, 75, 696, (1949), DOI 10.1103/PhysRev.75.696.

[2] - Fang Kaihong et al.:
Half life of ¹⁷⁵Hf.
In: Applied Radiation and Isotopes, 70, 10, (2012), DOI 10.1016/j.apradiso.2012.06.010.

[3] - K. N. Kmak et al.:
Measurement of the ¹⁷⁵Hf half-life.
In: Physical Review C, 111, 024308, (2025), DOI 10.1103/PhysRevC.111.024308.