Knowledge Bank

The Paramagnetic $Mn5$ molecule has been produced in the solid rare-gas matrices. It has been determined that S=25/2 from the number of observed fine structure lines. In Krypton and xenon matrices the molecule is strongly oriented, showing that $Mn5$ has axial symmetry. From spin and symmetry consider-actions a pentagonal geometry is indicated. $\mathrm{<mrow\; data-mjx-texclass="ORD">55</mrow>}Mn$ hyperfine splitting is unresolved but from the FWHM of each fine structure line $A11(55Mn)$ and $A\perp (55Mn)$ are estimated to be about 6 Gauss. This small splitting supportive of a bonding scheme utilizing largely the 4s orbitals with five non-bonded 3d electrons on each atom remaining unpaired. Tentative assignments indicate that $g11=1.988(3),g\perp -1.996(3)$, and the zero-field splitting parameters $|b\circ 2|=|D|=415(3)MHz$ and $|b\circ 4|=0.03(1)Mhz$ in solid krypton.