Crystallinity in apatites: how can a truly disordered fraction be distinguished from nanosize crystalline domains?

摘要: In the last decade synthetic apatites mimicking human natural one have been widely prepared and characterized from physico-chemical point of view; however a shading zone is still remaining related to evaluation distinction less crystalline part, almost amorphous, crystallographically well ordered, nano-sized inside apatite itself. Actually forming bone tissue can include both types crystals whose prevalence dependent specific evolution stage specialized performance. The quantitative description such combination usually represents puzzling problem, but result also clarify definition "crystallinity in apatite" that appears controversial. Many different apatites, including those nucleated on organic templates, were analyzed with techniques (X-ray diffraction, transmission electron microscopy, so on) true nature disordered part. results, manipulated by classical methodologies devised for substances highly perturbed structural order, led establish only specifically amorphous calcium phosphate really glass, while distorted portion coexisting more or regions simply nanocrystalline. Moreover, at conceptual limit crystallinity tending zero, two models surprisingly cease be conflicting.