Sb 3d5/2 binding energy values [1].
Curve-fitted Sb 3d XPS spectrum.
A) Doublet separation for Sb 3d5/2 - Sb 3d3/2 = 9.38 +/- 0.08 eV (5 Cit.).
[2] specifies a doublet separation of 9.34 eV.

B) Sb 3d5/2 overlaps with the O 1s spectrum. Need to fit and constrain the Sb 3d5/2 and Sb 3d3/2 peaks using the 3d3/2 peaks as a guide.  Remaining area in the 3d5/2 area will be due to O 1s signal.

C) Sb2O3 standard samples has Sb 3d5/2 at 530.1 to 530.3 eV. Sb2O5 standard sample at 530.9 eV.

D) Sb2S3 standard sample (Stibnite mineral sample) has Sb 3d5/2 peak at 529.6 eV. S 2p3/2 at 161.2 eV.

E) KSbO3 standard sample has Sb 3d5/2 peak at 530.7 eV.  K 2p3/2 at 292.8 eV.

[1] C.D. Wagner, A.V. Naumkin, A. Kraut-Vass, J.W. Allison, C.J. Powell, J.R.Jr. Rumble, NIST
Standard Reference Database 20, Version 3.4 (web version) (http:/ 2003.
[2] J.F. Moulder, W.F. Stickle, P.E. Sobol, K.D. Bomben, Handbook of X-ray Photoelectron Spectroscopy, Perkin-Elmer Corp., Eden Prairie, MN, 1992.