Transition-metal fluoride ions, MF(n)(+) from gas-phase reactions of nascent laser-ablated M(+) with fluorocarbons

The positive-ion products of the direct reaction of nascent (energetic) laser-ablated metal ions (M(+)) with fluorocarbons were determined by time-of-flight mass spectrometry. Several lanthanide, second- and third-row transition-metal ions were studied to provide a survey of reactivities. Whereas Pt+, Au+ and Al+ were apparently inert, the other M(+) ions studied - Ce+, Eu+, Tb+, Dy+, Ho+, Er+, Yb+, Zr+, Hf+, Nb+, Ta+ and W+ - reacted to varying degrees, abstracting atoms from the reactant gas to produce metal fluoride ions, MF(n)(+). The relative metal-ion reactivities generally closely paralleled those of the corresponding metals, and the product distribution - the values of n in MF(n)(+) - reflected essential aspects of the elemental chemistries. Thus the oxidation state in the largest fluoride ions revealed the highest normally accessible oxidation states: MF(n)(+) were formed up to n = 2, 3, 4 and 5 for Ho, Hf, Ta and W, respectively. Significant discrepancies in product distributions were found between some homologous M(+); reactivity variations across the lanthanide series reflected specific electronic configurations. The results are pertinent to processes which occur in mass spectrometer ion sources and pulsed laser deposition, and the technique is applicable to the microscale study of scarce or radioactive elements.