Although Figure displays general trends for speciation in NaOH-based hydrofluxes, the nature of minor products suggests additional richness for the design of hydroxyapatite phases. Indeed, the Sr5(MnO4)3OH structure can be detected as secondary phase for q(Na) = 1 and q(Sr)) ≤ 2 (Figure ), hence away from the predominance area for Sr5(MnO4)3OH as main product. In these conditions and contrary to all other compositions probed without Cl -ions by using Sr(OH)2, the relative intensities of the hydroxyapatite XRD peaks are consistent with those expected from the tabulated crystal structure, indicating no marked anisotropic growth. The corresponding reflections are also broader than in other conditions, suggesting a smaller size of crystalline domains. We then explored smaller q(H2O)Na values, hence lower water content, to isolate this specific form of hydroxyapatite. At q(H2O)Na = 0.5, according to XRD (Figure ), no matter the q(Sr) value, Sr5(MnO4)3OH is the only crystalline Mn phase. The only byproduct is SrCO3, more prominent at high q(Sr) due to the excess of Sr(OH)2 supplied to the reaction medium and its strong tendency to carbonation. No significant preferential orientation is detected. The corresponding peaks are again wider than in the large q(H2O)A range (Figure ), suggesting smaller crystallites.