Does Cm-247 count as a third Mattauch violation?

[snorkack]

Notorious Mattauch violations are:
Sb-123 and Te-123 (both stable)
Hf-180 and Ta-180 (both stable)
But should Cm-247 and Bk-247 also count?
Both are radioactive - but only to alpha decay and, in case of Bk-247, fission.
Does the absence of electron capture or beta decay count as third Mattauch violation?

 

[mfb]

Are you sure there are no beta decays or electron capture possible? The non-observation doesn’t mean they don’t exist, especially for exotic nuclides.

 

[Vanadium 50]

Bk-247 decays by beta emission to Cm-247. However it will be very slow: possibly millions of years.

 

[snorkack]

Bk-247 decays by beta emission to Cm-247. However it will be very slow: possibly millions of years.

By both emission and capture, or by capture alone?

 

[mfb]

You can look up the masses and calculate it yourself.

 

[Vanadium 50]

That was very polite.

 

[snorkack]

I seem to get
Cm-247: 247.070354
Bk-247: 247.070307

Is that the mass of atom, with electrons?

 

[mfb]

Yes.

 

[snorkack]

Which means that it is Cm-247 which is heavier.

 

[mfb]

Right.

 

[snorkack]

Right.

Then might Cm-247 undergo beta decay?
Cm-247 is also notable for absence of spontaneous fission.

 

[mfb]

Then might Cm-247 undergo beta decay?

It is not impossible. With the tiny energy difference and the large spin difference it is extremely unlikely, however.