Tomazic B B, Nancollas G H
Invest Urol. 1979 Mar;16(5):329-35.
The precipitation of calcium oxalates may involve transformation from a metastable hydrate such as calcium oxalate trihydrate, COT, to the thermodynamically stable monohydrate, COM. A highly reproducible seeded crystal growth method has been used to study this transformation reaction over a range of temperatures and in ionic media such as the chlorides of sodium, potassium, and magnesium. After the initial dissolution of COT, the calcium concentration remains constant for prolonged periods while appreciable nucleation and growth of COM takes place concomitantly with COT dissolution. The transformation is markedly dependent on temperature, composition, and concentration of ionic media. In urines, the hydrate conversion is appreciably slower and the rate depends upon the method of pretreatment. In these cases, evidence is advanced for the formation of other phases such as the calcium phosphates.
草酸钙的沉淀可能涉及从亚稳水合物（如三水合草酸钙，COT）向热力学稳定的一水合物（COM）的转变。一种具有高度可重复性的晶种生长方法已被用于研究在一系列温度以及在诸如钠、钾和镁的氯化物等离子介质中的这种转变反应。在COT初始溶解后，钙浓度在较长时间内保持恒定，而COM的显著成核和生长与COT溶解同时发生。这种转变明显取决于离子介质的温度、组成和浓度。在尿液中，水合物转化明显较慢，且速率取决于预处理方法。在这些情况下，有证据表明会形成其他相，如磷酸钙。
