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首页> 外文期刊>Crystal growth & design >Disordering the Disorder as the Route to a Higher Order: Incoherent Crystallization of Calcium Phosphate through Amorphous Precursors
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Disordering the Disorder as the Route to a Higher Order: Incoherent Crystallization of Calcium Phosphate through Amorphous Precursors

机译：使病症作为到更高阶的途径：通过无定形前体的磷酸钙结晶不连贯结晶

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Understanding the stability and phase transformations of amorphous materials may open the way toward structurally complex, nonequilibrium structures that are the future of materials science. Elucidating the ultrafine specifics of the transition of amorphous calcium phosphate (ACP) to hydroxyapatite (HAp) and other crystalline calcium phosphate (CP) phases may also pave the way for the development of nondrug, acellular, and purely materials-based therapies for a number of osteopathic conditions. Reports on classical and nonclassical mechanisms of nucleation and growth of HAp abound, but here it is shown that these two modes of growth are wedded during the crystallization of HAp from an amorphous precursor. This process combines growth via ionic units, atomic clusters, and spheroid amorphous nanoparticles of variable sizes as well as via internal lattice rearrangements and is typified by a mechanistic multiplicity that agrees well with the pleiotropy and protean nature of this material. Formation and retention of the alpha-polymorph of tricalcium phosphate (TCP) exclusively in a material formed through amorphous precursors under a specific annealing regimen and the diffractometric pattern matching indicated that ACP structurally resembles alpha-TCP more than beta-TCP or HAp. Crystallographic symmetry comparison between HAp and alpha-TCP-like ACP was provided in support of this match, primarily focusing on the greater void concentration in alpha-TCP than in other TCP polymorphs and the similarities in the pseudohexagonal arrangement of ionic columns in HAp and alpha-TCP. The elimination of structural water correlated with the closing of the amorphous structure in the first stages of phase transformation and was entailed by the red shift of P-O stretches and the blue shift of the O-P-O bending vibration modes as well as by the reduction of the high-index (434) and (264) lattice constants of alpha-TCP-like ACP. Meanwhile, the environment around Ca-O and OH groups varied
机译：了解无定形材料的稳定性和相变可能在结构复杂的情况下开辟道路，这是材料科学的未来。阐明无定形磷酸钙（ACP）转变为羟基磷灰石（HAP）和其他结晶磷酸钙（CP）阶段的超细细节也可以为数字的非晶，无细胞和纯材料的疗法铺平道路骨疗法条件。报告HAP成核和生长的古典和非生长机制比比皆是，但在这里表明，在从非晶前体的结晶过程中结晶这两种生长模式。该方法通过离子单元，原子簇和变量尺寸的球状无定形纳米颗粒以及通过内部晶格重排的生长结合，并且通过机械多重性典型，其与这种材料的Pleiotropy和Protean的本质一致。在特定退火方案下通过非晶前体形成的磷酸三钙（TCP）的形成和保留α-多晶型物，并且衍射图案匹配表明，ACP在结构上类似于β-TCP或HAP。提供了HAP和α-TCP样ACP之间的结晶对称比较，其支持这一匹配，主要关注α-TCP中的更大的空隙浓度，而不是其他TCP多晶型物和HAP和α的离子柱的伪峰排列中的相似性-TCP。在相变的第一阶段中消除与无定形结构的关闭相关的结构水，并被PO拉伸的红色偏移和OPO弯曲振动模式的蓝色偏移以及高度的降低α-TCP样ACP的索引（434）和（264）晶格常数。同时，CA-O周围的环境和oh组各种各样的环境

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