The epitaxial growth of phosphorus on the Au(111) surface has been considered a candidate for the synthesis of a layer of P with a buckled graphene-like structure. The formation of a (5 ) superstructure is observed by low energy electron diffraction and scanning tunneling microscopy and is commonly referred to as “blue phosphorus” or “blue phosphorene”. Its structural details are interesting because they contribute to the fundamental understanding of the growth of 2D materials at metal interfaces. However, the structural investigations made so far provide different and conflicting models for this structure. Earlier models propose the growth of a pure buckled P layer. More recently, the formation of a P-Au network with Au adatoms interlinking aggregates of 9 P atoms has been suggested. Here, we report an analysis of the (5 )P/Au(111) superstructure by photoelectron spectroscopy and the normal incidence x-ray standing wave (NIXSW) technique, which is especially suited to determine vertical bonding distances of adsorbates at surfaces. We find a structure where the P atoms are at two heights (defining layers) which are 3.53 and 2.48 (buckling 1.05 ) above the Au surface, with a ratio of P atoms per area of about 1 : 2.64 for the top layer with respect to the bottom layer. For the bottom layer, two types of P atoms (39 % :61 %) can be discerned in the photoemission spectrum by a chemical shift. The smaller fraction (39%) is attributed to P atoms linked to Au adatoms. This finding, along with the conclusions from the Au7f photoemission spectra, strongly supports the P-Au network model. In addition, our analysis also provides an independent determination of the heights of the P atoms with respect to the Au surface.