Gallium oxide hydroxide (GaOOH·xH2O) single crystals were synthesized in aqueous solutions by using two different precipitation techniques: homogeneous decomposition of urea and forced hydrolysis in pure water. Precipitation of crystals started at exactly the same pH value (i.e., 2.05 at 85°C) in both cases. The morphology of crystals turned out to be quite different (zeppelin-like with urea, rodlike without urea) in each of the above methods. Calcination of these gallium oxide hydroxide crystals in air at temperatures ≥500°C transformed them into Ga2O3. Characterization of the samples was performed by X-ray diffractometry, scanning electron microscopy, thermogravimetry/differential thermal analysis, Fourier transform infrared spectroscopy, and ICP, carbon, and nitrogen analyses.

中文翻译：

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含或不含尿素水溶液中氢氧化镓晶体的合成及其煅烧行为

通过使用两种不同的沉淀技术：尿素的均相分解和在纯水中强制水解，在水溶液中合成了氢氧化镓 (GaOOH·xH2O) 单晶。在这两种情况下，晶体的沉淀开始于完全相同的 pH 值（即 85°C 时为 2.05）。在上述每种方法中，晶体的形态都非常不同（有尿素的齐柏林飞艇状，没有尿素的棒状）。这些氧化镓氢氧化物晶体在空气中在 ≥ 500°C 的温度下煅烧，将它们转化为 Ga2O3。通过 X 射线衍射、扫描电子显微镜、热重/差热分析、傅里叶变换红外光谱以及 ICP、碳和氮分析对样品进行表征。