The electron impact mass spectrum of Mo2(S2PF2)4 shows the molecular i
on which releases a PF2 group to produce the most abundant ion, Mo2S8P
3F6+. This ion fragments by releasing a series of groups such as PF2,
PFS and PF2S. For Mo2(S2PMe2)4 Desorption Chemical Ionization (DCI) te
chnique is required to see the molecular ion. The parent ion fragments
by the loss of Me2S, PMe2S and PMe3 groups. Loss of PMe3 from molecul
ar ion suggests rearrangement before fragmentation-a process not obser
ved for Mo2(S2PF2)4. The difference in mass spectral fragmentation pat
terns is in agreement with the different structures of the two compoun
ds.