The importance of stabilizing ligands cannot be understated for the colloidal synthesis of nanoparticles as well as their dispersion and assembly into macro-structures such as electrodes. We have recently demonstrated a novel all-inorganic ligand approach to Pt nanoparticle synthesis where surface-adsorbed Sn serves as both reducing agent and stabilizing ligand, producing remarkably monodispersed nanoparticles. By eliminating the need to remove organic surfactants prior to nanoparticle incorporation into electrodes, we were able to use electrostatic assembly to achieve well-defined nanoparticle dispersions in contrast to the aggregated structures common in the field. The approach has allowed us to elucidate the nature of structure sensitivity for electrocatalytic oxygen reduction reaction in acidic and alkaline media. In this paper, we provide a detailed investigation of the evolution of surface-adsorbed Sn-Pt ligand interaction during Pt nanoparticle growth. We show that surface adsorbed SnCl3 exists as pyramidally coordinated to the Pt nanoparticle through Sn-Pt bond formation, resulting in a distorted tetrahedrally coordinated Sn-moiety. Furthermore, we show the shift in the bond charge distribution as the Pt is reduced from its initial Pt2+ state to its metallic state. Direct evidence for the distorted tetrahedral coordination of Pt-SnCl3 and the shift in Sn-Pt bond charge during nanoparticle growth emerges from the Sn-119 Mossbauer quadrupole splitting (QS) and Isomer-shift (IS) respectively. Evolution of the structure and chemistry of inorganic complexes during nanoparticle growth has never before been demonstrated and our work is the first to identify the strength of the Sn-Pt interaction in these systems. Such an understanding of nanoparticle surface chemistry will permit extension of this technique to other metals and macro-structures. (C) 2018 Elsevier B.V. All rights reserved.