The densities of several liquid lanthanoid sesquioxides (Ln₂O₃, Ln = Er, Ho, Tb, Gd) were measured over the temperature range from 2700 K (the approximate melting point of these materials) to 3200 K. These measurements were performed using the Electrostatic Levitation Furnace onboard the International Space Station (ISS‐ELF). Based on the Coulomb force between the charged samples and surrounding electrodes and employing a rapid feedback control process, specimens were stably levitated and subsequently melted by high power lasers. The molten oxides exhibited spherical morphologies and their volumes were readily calculated from magnified images. Subsequent weighing of the samples on Earth allowed the densities of the oxides to be determined. The densities of Er₂O₃, Ho₂O₃, Tb₂O₃, and Gd₂O₃ at their melting temperatures (T_m) were found to be 8170, 8035, 7451, and 7268 kg/m³, respectively, and these density values were shown to exhibit a linear correlation with temperature. The molar volumes of these oxides at their T_m values were calculated and compared with those of other sesquioxides (Al₂O₃, Ga₂O₃, and B₂O₃). The molar volumes of the nonglass‐forming sesquioxides (Er₂O₃, Ho₂O₃, Tb₂O₃, Gd₂O₃, Al₂O₃, and Ga₂O₃) showed linear correlations with the cubes of their cation radii, whereas those of the glass‐forming oxide (B₂O₃, As₂O₃, and Sb₂O₃) showed different correlations.

中文翻译：

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在国际空间站用静电悬浮炉测量的液态镧系元素倍半氧化物的密度

在2700 K（这些材料的近似熔点）至3200 K的温度范围内测量了几种液态镧系倍半氧化物（Ln ₂ O ₃，Ln = Er，Ho，Tb，Gd）的密度。国际空间站（ISS‐ELF）上的静电悬浮炉。基于带电样品和周围电极之间的库仑力，并采用快速反馈控制过程，使样品稳定悬浮并随后通过大功率激光熔化。熔融氧化物呈现球形形态，其体积易于从放大图像中计算出来。随后对地球上的样品进行称重，可以确定氧化物的密度。Er ₂的密度发现在其熔融温度（T _m）下的O ₃，Ho ₂ O ₃，Tb ₂ O ₃和Gd ₂ O ₃分别为8170、8035、7451和7268 kg / m ³，这些密度值为显示出与温度呈线性关系。计算这些氧化物在其T _m值时的摩尔体积，并将其与其他倍半氧化物（Al ₂ O ₃，Ga ₂ O ₃和B ₂ O ₃）。非玻璃形成的倍半氧化物（Er ₂ O ₃，Ho ₂ O ₃，Tb ₂ O ₃，Gd ₂ O ₃，Al ₂ O ₃和Ga ₂ O ₃）的摩尔体积与它们的阳离子立方呈线性关系。半径，而玻璃氧化物（B ₂ O ₃，As ₂ O ₃和Sb ₂ O ₃）的半径显示出不同的相关性。