Abstract Amorphous materials are of interest in the genesis of crystalline solids. They are often the first to precipitate from supersaturated solutions and are in the nanometer size range, transforming into a nanocrystalline metastable phase, and then to thermodynamically stable phases. One must seek knowledge of the composition, structure, thermodynamics, kinetics, and reaction pathways that relate the amorphous and crystalline phases. The subject of this study is the amorphous phases in the system RE2O3−CO2–H2O (RE- La, Nd, Dy,Yb). They were synthesized via direct precipitation and urea hydrolysis, and characterized by powder XRD, DTA with mass spectrometric analysis of the evolved gases. Phases have the non-stoichiometric composition RE2O3·xCO2·yH2O (1

中文翻译：

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RE2O3-CO2-H2O 系统中无定形稀土 (RE) 碳酸盐的形成和能量学

摘要 无定形材料在结晶固体的形成中很受关注。它们通常最先从过饱和溶液中沉淀出来，尺寸在纳米范围内，转变为纳米晶亚稳态相，然后转变为热力学稳定相。人们必须了解与非晶相和晶相相关的组成、结构、热力学、动力学和反应途径。本研究的主题是系统 RE2O3-CO2-H2O（RE-La、Nd、Dy、Yb）中的非晶相。它们通过直接沉淀和尿素水解合成，并通过粉末 XRD、DTA 和逸出气体的质谱分析进行表征。相具有非化学计量组成 RE2O3·xCO2·yH2O (1