Calcite is the most abundant carbonate mineral in Earth's crust. Upon cleavage, the (10.4) plane with a rectangular unit cell is exposed. Interestingly, several experiments suggest a (2 × 1) surface reconstruction. However, clear experimental evidence and a theoretical confirmation were long missing. Recently, convincing indication for a (2 × 1) reconstruction has been given by atomic force microscopies taken at 5 K. Here, we show temperature-programmed desorption (TPD) experiments of water and ethanol desorbing from calcite (10.4) around room temperature. The TPD curves fit excellently to a kinetic model considering two different adsorption sites, as expected in case of a (2 × 1) reconstruction. This finding applies to the desorption of water and ethanol, illustrating that the effect is characteristic for the calcite cleavage plane. Our results thus show that the (2 × 1) reconstruction not only exists at room temperature but has significant impact on the interfacial properties of calcite.

中文翻译：

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水如何从方解石中解吸

方解石是地壳中含量最丰富的碳酸盐矿物。解理后，暴露出具有矩形晶胞的 (10.4) 面。有趣的是，一些实验表明 (2 × 1) 表面重建。然而，长期以来一直缺乏明确的实验证据和理论证实。最近，在 5 K 下拍摄的原子力显微镜给出了 (2 × 1) 重建的令人信服的指示。在这里，我们展示了水和乙醇在室温附近从方解石 (10.4) 解吸的程序升温解吸 (TPD) 实验。TPD 曲线非常适合考虑两个不同吸附位点的动力学模型，正如在 (2 × 1) 重建的情况下所预期的那样。这一发现适用于水和乙醇的解吸，说明该效应是方解石解理面的特征。