Cluster growth model for hydroxyapatite
Cluster growth model for hydroxyapatite
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DOI：
10.1021/cm980062c
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发表时间：
1998-11-01
影响因子：
8.6
通讯作者：
Ito, A
中科院分区：
文献类型：
--
作者：
Onuma, K;Ito, A
强度增强的动态光散射技术揭示了磷酸钙簇的存在下，从0.7至1.0 nm的大小在模拟体液中。簇也存在于流体不饱和相对于octacalcium和无定形磷酸钙和过饱和相对于羟基磷灰石。这些簇是羟基磷灰石的生长单元，这是从羟基磷灰石以0.8或1.6nm的高度通过阶跃流动生长的事实来判断的，并且如先前所揭示的，生长单元掺入晶体中的概率极低。我们提出了一个簇生长模型，其中羟基磷灰石生长的选择性六方堆积的左，右手手性Ca-9-（PO 4）（6）簇0.8 nm的大小。从理论上讲，层错的集群创建一个反射孪晶，边缘位错与C/2的伯格斯矢量和螺旋位错。反射孪晶的一个例子是常在镉氯磷灰石中发现的半面体孪晶。在合成的单晶羟基磷灰石表面上实际获得了对应于Burgers矢量为C/2的刃位错的原子图像。
An intensity-enhanced dynamic light scattering technique revealed the presence of calcium phosphate clusters from 0.7 to 1.0 nm in size in a simulated body fluid. The clusters were also present in fluids undersaturated with respect to octacalcium and amorphous calcium phosphates and supersaturated with respect only to hydroxyapatite. These clusters are the growth unit of hydroxyapatite judging from the fact that hydroxyapatite grows by step flow 0.8 or 1.6 nm in height and that the probability of incorporation of the growth unit into the crystal is extremely low, as revealed previously. We propose a cluster growth model where hydroxyapatite grows by selective hexagonal packing of left- and right-handed chiral Ca-9-(PO4)(6) clusters 0.8 nm in size. Theoretically, stacking faults of clusters create a reflection-twin crystal, edge dislocations with a Burgers vector of C/2 and screw dislocations. An example of the reflection-twin is the merohedry twin which is frequently found in cadmium chlorapatite. An atomic image corresponding to the edge dislocations with a Burgers vector of C/2 was actually obtained on the surface of synthetic single-crystal hydroxyapatite.