Mendelevium-244

Properties and data of the isotope ²⁴⁴Md.

Content

Mendelevium-244 is a radioisotope of the chemical element Mendelevium, which, in addition to the element-specific 101 protons, has 143 neutrons in the atomic nucleus, resulting in the mass number 244. The very short-lived, only artificially producible, unstable and therefore radioactive nuclide has no practical significance; dealing with ²⁴⁴Md is for academic purposes only.

The discovery of the Mendelevium isotope with mass 244 was first reported in 2020. The researchers found evidence that Md-244 has two separate decay chains, each resulting in a different half-life: 0.4 seconds and 6 seconds, respectively, based on different energy configurations of the particles in its atomic nucleus.

For the values presented here: see also [3].

General data

Name of the isotope:Mendelevium-244; Md-244Symbol:²⁴⁴Md or 244101MdMass number A:244 (= number of nucleons)Atomic number Z:101 (= number of protons)Neutrons N:143Isotopic mass:244.08116(40) u (atomic weight of Mendelevium-244)Nuclide mass:244.0257617 u (calculated nuclear mass without electrons)Mass excess:75.60005 MeVMass defect:1.94825122 u (per nucleus)Nuclear binding energy:1814.78432192 MeV (per nucleus)
7.43764066 MeV (average binding energy per nucleon)Separation energy:
S_P = 1.008(396) MeV (first proton)Half-life:0.38 sDecay constant λ:1.8240715277893 s^-1Specific activity α:4.501973638912 × 10⁺²¹ Bq g^-1
121674963213.86 Ci g^-1Spin and parity:
(nuclear angular momentum)Year of discovery:2020

Radioactive Decay

Half-life T_½ = 0.38 s respectively 3.8 × 10^-1 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
α	²⁴⁰Es	> 86 %	8.947(79) MeV
EE/β⁺	²⁴⁴Fm	< 14 %	6.633(425) MeV

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
^244mMd		5 ms

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 143) and isobaric (same nucleon number A = 244) with Mendelevium-244. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 143	Isobar A = 244
84	²²⁷Po
85	²²⁸At
86	²²⁹Rn
87	²³⁰Fr
88	²³¹Ra
89	²³²Ac
90	²³³Th
91	²³⁴Pa
92	²³⁵U
93	²³⁶Np	²⁴⁴Np
94	²³⁷Pu	²⁴⁴Pu
95	²³⁸Am	²⁴⁴Am
96	²³⁹Cm	²⁴⁴Cm
97	²⁴⁰Bk	²⁴⁴Bk
98	²⁴¹Cf	²⁴⁴Cf
99	²⁴²Es	²⁴⁴Es
100	²⁴³Fm	²⁴⁴Fm
101	²⁴⁴Md	²⁴⁴Md

Literature and References

[1] - J. L. Pore et al.:
Identification of the New Isotope ²⁴⁴Md.
In: Physical Review Letters, (2020), DOI 10.1103/PhysRevLett.124.252502.

[2] - J. Khuyagbaatar, H. M. Albers, M. Block et al.:
Search for Electron-Capture Delayed Fission in the New Isotope ²⁴⁴Md.
In: Physical Review Letters, 125, 142504, (2020), DOI 10.1103/PhysRevLett.125.142504.

[3] - F. P. Heßberger, M. Block, Ch. E. Düllmann, A. Yakushev, M. Leino, J. Uusitalo:
Some Remarks on the Discovery of ²⁴⁴Md.
In: Physical Review Letters, 126, 182501, (2021), DOI 10.1103/PhysRevLett.126.182501.