ABSTRACT The low temperature heat capacity of Cs2Si4O9, which is one of the cesium chemisorbed compounds onto stainless steel during severe accidents of the light water nuclear reactor, was experimentally determined for the first time in the temperature range of 1.9–302 K. The experimentally determined heat capacity, Cp o (298.15 K), and the standard entropy, So (298.15 K), were 249.4 ± 1.1 J K−1 mol−1 and 322.1 ± 1.3 J K−1 mol−1, respectively. The standard Gibbs energies of formation of Cs2Si4O9 at high temperatures, ∆fGo (T), were reevaluated by using the presently obtained So (298.15 K) and the previously reported experimental results of the standard enthalpy of formation, ∆fHo (298.15 K), and the standard enthalpy increments at high temperatures, Ho (T)-Ho (298.15 K).

中文翻译：

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Cs2Si4O9的低温热容

摘要 Cs2Si4O9 是轻水核反应堆严重事故中铯化学吸附在不锈钢上的化合物之一，其低温热容是首次在 1.9-302 K 温度范围内进行实验测定。热容 Cp o (298.15 K) 和标准熵 So (298.15 K) 分别为 249.4 ± 1.1 JK-1 mol-1 和 322.1 ± 1.3 JK-1 mol-1。通过使用目前获得的 So (298.15 K) 和先前报告的标准生成焓 ΔfHo (298.15 K) 的实验结果，重新评估了在高温下形成 Cs2Si4O9 的标准吉布斯能量 ΔfGo (T)，高温下的标准焓增量 Ho (T)-Ho (298.15 K)。