Abstract C3S, the main constituent in Portland cement, incorrectly has been denominated as tricalcium silicate at times when analytical instrumentation did not allow to uncover its actual chemical constitution. Today, we know that it is composed of three building blocks, namely Ca2+, SiO44− tetrahedra and interspersed oxide anions, O2−. Consequently, its scientifically correct designation is tricalcium oxy silicate, and its formula needs to be written as Ca3O(SiO4) when indicating its chemical constitution, while Ca3SiO5 only represents an empirical or sum formula. The presence of separate O2– anions in its structure is responsible for its different hydration behavior and higher basicity (release of Portlandite), as compared to C2S. Consequently, it is proposed to henceforth exclusively use the scientifically correct designation tricalcium oxy silicate and the formula Ca3O(SiO4). Moreover, it is suggested to abandon the oxide-based abbreviations 3CaO·SiO2, 2CaO·SiO2 and 3CaO·Al2O3 for the clinker phases as they grossly misrepresent their actual chemical constitution.

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关于 C3S、氧硅酸三钙的正确化学命名法

摘要 C3S 是波特兰水泥的主要成分，在分析仪器无法揭示其实际化学成分的情况下，有时会错误地将其命名为硅酸三钙。今天，我们知道它由三个构件组成，即 Ca2+、SiO44- 四面体和散布的氧化物阴离子 O2-。因此，其科学上正确的名称是三氧化二硅酸三钙，在表示其化学组成时，其分子式需要写为Ca3O(SiO4)，而Ca3SiO5仅代表经验式或总和式。与 C2S 相比，其结构中存在单独的 O2- 阴离子是其不同水合行为和更高碱度（硅酸盐的释放）的原因。最后，建议此后仅使用科学上正确的硅酸三钙名称和化学式 Ca3O(SiO4)。此外，建议放弃用于熟料相的基于氧化物的缩写 3CaO·SiO2、2CaO·SiO2 和 3CaO·Al2O3，因为它们严重歪曲了它们的实际化学组成。