Magnesium whitlockite structure

Abstract

Magnesium whitlockite (Mg-WH), the second most abundant inorganic material in hard tissue, is a promising biomaterial and participates in cell signaling through piezoelectric modulation. However, its electric structure is not fully understood. This study investigated the structure and electronic structure of Mg-WH for the first time using ab initio methods. Additionally, Mg-WH was synthesized through the coprecipitation method and characterized by scanning electron microscopy (SEM-FEG), X-ray diffraction (XRD), and Fourier-transform infrared (FTIR) spectroscopy. The experimental results of XRD were compared with those obtained by computational simulation, and good agreement was shown. The Ca1 site of Mg-WH showed a higher distance between magnesium and other coordinated oxygens, making it more likely to accommodate atomic substitution in Mg-WH doping concerning elements with ionic radii bigger than Mg2+. Besides, the theoretical model confirmed the presence of a hydrogen bond due to the presence of the HPO42-group at the Ca4 site, which was further confirmed by the experimental FTIR spectrum. This hydrogen bond and Mg2+ in Mg-WH may play an essential role in physiological environments.