INTERMEDIATE PHASES IN BASIC SOLUTION PREPARATION OF ALKALINE EARTH PHOSPHATES
INTERMEDIATE PHASES IN BASIC SOLUTION PREPARATION OF ALKALINE EARTH PHOSPHATES
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DOI：
10.1007/bf02279192
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发表时间：
1968-01-01
期刊：
影响因子：
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通讯作者：
POSNER, AS
中科院分区：
文献类型：
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作者：
EANES, ED;POSNER, AS
从碱性溶液中析出的磷酸钙中的第一个固体在结构上是非晶态的。然而，溶液制备的非晶态正磷酸盐的存在不仅仅是磷酸钙体系所特有的。在类似的条件下也可以制备非晶态磷酸镁和磷酸铵镁，但与转化为羟基磷灰石的钙盐不同，后者显然是溶液稳定的。从碱性溶液中制备正磷酸锶和正磷酸钡不会产生非晶态中间体。锶的中间相为Sr3(PO4)2·4H2O，而Ba2+则以稳定的羟基磷灰石形式析出。然而，磷酸三锶会自动催化转化为锶羟基磷灰石。锶中间体与无定形磷酸钙相似的化学计量比和相同的动力学行为表明，后者可能是磷酸三钙而不是隐晶的缺钙羟基磷灰石。这支持了这样一种可能性，即骨矿物中的非晶相可能不是磷灰石，而是一种截然不同的独立化合物。
The first solid to appear in the precipitation of calcium phosphates from basic solutions is structurally non-crystalline. The existence, however, of a solution-prepared, non-crystalline orthophosphate salt is not unique only to the calcium phosphate system. Non-crystalline magnesium phosphates and magnesium ammonium phosphates can also be prepared under comparable conditions, but unlike the calcium salt, which converts into hydroxyapatite, these latter compounds are apparently solution stable. Preparations of strontium and barium orthophosphates from basic solution do not yield non-crystalline intermediates. For strontium, the intermediate phase is Sr3(PO4)2·4H2O, whereas the barium precipitates immediately as a stable barium hydroxyapatite. The tristrontium phosphate, however, converts autocatalytically into strontium hydroxyapatite. The analogous stoichiometry and identical kinetic behavior of the strontium intermediate with that of the amorphous calcium phosphate suggest that the latter could be a tricalcium phosphate rather than a cryptocrystalline Ca-deficient hydroxyapatite. This supports the possibility that the non-crystalline phase in bone mineral may not be an apatite but instead a distinct and separate compound.