  The fundamental construct of organic chemistry involves understanding
molecular behavior through functional groups. Much of computational chemistry
focuses on this very principle, but metallic materials are rarely analyzed
using these techniques owing to the assumption that they are delocalized and do
not possess inherent functionality. In this paper, we propose a methodology
that recovers functional groups in metallic materials from an energy
perspective. We characterize neighborhoods associated with functional groups in
metals by observing the evolution of Bader energy of the central cluster as a
function of cluster size. This approach can be used to conceptually decompose
metallic structure into meaningful chemical neighborhoods allowing for
localization of energy-dependent properties. The generalizability of this
approach is assessed by determining neighborhoods for crystalline materials of
different structure types, and significant structural defects such as grain
boundaries and dislocations. In all cases, we observe that the neighborhood
size may be universal - around 2-3 atomic diameters. In its practical sense,
this approach opens the door to the application of chemical concepts, e.g.,
orbital methods, to investigate a broad range of metallurgical phenomena, one
neighborhood at a time
