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We developed a new and injectable poly‐dicalcium phosphate dihydrate (P‐DCPD) forming cement. The key structural difference between P‐DCPD and classical DCPD is that P‐DCPD is composed of interconnected P‐DCPD crystals by interlocking to the polyphosphate chains. In contrast, DCPD is composed of a package of DCPD crystals with weak mutual ionic bonding. The purpose of this continuing study was to compare the physicochemical properties between P‐DCPD and DCPD cement particles. Data collected from SEM, X‐ray diffraction, and Raman Spectroscopy approaches demonstrated that P‐DCPD has a more stable chemical structure than DCPD as evidenced by much less transformation to hydroxyapatite (HA) during setting. Nanoindentation showed a similar hardness while the elastic modulus of P‐DCPD is much lower than DCPD that might be due to the much less HA transformation of P‐DCPD. P‐DCPD has much lower zeta potential and less hydrophilicity than DCPD because of its entangled and interconnected polyphosphate chains. It is expected that superhydrophilic DCPD undergoes faster dissolution than P‐DCPD in an aqueous environment. Another interesting finding is that the pH of eluent from P‐DCPD is more neutral (6.6–7.1) than DCPD (5.5–6.5). More extensive experiments are currently underway to further evaluate the potential impacts of the different physiochemical performance observed of P‐DCPD and DCPD cement particles on the biocompatibility, degradation behavior and bone defect healing efficacy both in vivo and in vitro. [ABSTRACT FROM AUTHOR]