Molybdenum

A wide range of values are available for various Mo compounds.

Table 1. Average Mo 3d5/2 binding energy values from a compilation of literature sources [1].

Table 2. Binding energy and FWHM values from standard samples of Mo metal, MoO3 and MoS2. An asymmetric peak-shape definition is also given for the metal. Mo 3d5/2-3/2 splitting is ~3.13 eV.

Table 3. Mo oxide O 1s binding energy values from a compilation of literature sources [1].

Table 4. Binding energy values from a compilation of literature sources [1] for multiple core lines for MoS2.

P.A. Spevak also suggests a Mo 3d5/2 binding energy for Mo(V) species at 231.6 eV which may be useful for analysis of multivalent Mo compounds [2]. Mo(V) oxide can only be present if MoO3 is also present. This and other references [3] show the Mo 3d5/2 for Mo(V) to range from 231.6 to 231.9 eV.

Another important note to mention is the fact that MoO3 will reduce to Mo(V) species under the X-ray beam (one can see the fraction of Mo(V) species increasing over analysis time). MoO2 appears to be quite stable under X-ray bombardment.

References:

[1] http://srdata.nist.gov/xps/

[2] P.A. Spevack, N.S. McIntyre, J. Phys. Chem. 96 (1992) 9029–9035.
[3] C.R. Clayton, Y.C. Lu, Surf. Interface Anal. 14 (1989) 66–70.