Its precursor was grown with four different compositional feeds (Figure ), naturally giving it the largest compositional variation between surface and center. The Ni and Mn linescans showed systematic and rather reproducible intensity gradients within the three planes. For Mn, the gradient was indicated by an increase in intensity at either end of the linescans, i.e., from the particle center to either surface. The intensity increase appeared more evident in the YZ and XZ planes than in XY, hinting at heterogeneity within the 3D volume. Comparably clearer evidence of 3D heterogeneity was seen for Ni. Stark differences in intensity profiles were seen between all three planes, especially in the particle center, where the most extensive porosity was observed, particularly in the XY plane. Generally, the Ni intensity increased on either side of the center, reached a maximum, and then decreased to the edge. Lastly, in contrast to Ni and Mn, the intensity profiles of Co showed notable dispersion between different linescans in the same plane. Interestingly, similar profiles were clustered by radial position (i.e., the same color in Figure .), suggesting that perhaps the fluctuations could be arising from heterogeneity in the Co distribution. Despite the existence of trends that appeared systematic, these observations were vulnerable to noise, which requires the sampling of the entire structure to determine which trends were statistically significant.