  Resonant soft X-ray scattering was used to determine the presence of more
subtle orderings not detected in standard structural analyses. By tuning to
specific Co absorption edges, arrangements particular to the electronic states
of those elements are enhanced. We have discovered an ordering commensurate to
the lattice at the ($\frac{1}{4}~\frac{1}{4}~\frac{1}{4}$) position.
Incommensurate peaks near this position were also observed. The intensity of
these peaks depends on the oxygen concentration of the sample, and can be
suppressed at temperatures above 320 K. Regular orderings of charge density
which closely match the underlying lattice may help to explain the observed
propensity for SrCoO$_{3-y}$ (0 $\leq$ y $\leq\frac{1}{2}$) to stabilize at
particular phases.
