二酸化ゲルマニウム

解説化学式GeO2。二酸化ゲルマニウムは，無色の固体で，水に可溶性の六方晶系に属する結晶と，不溶性の正方晶系に属する結晶とがある。転移温度は1033℃で，水溶性のほうが低温で安定である。正方晶系の結晶の密度は6.24g/cm3で融点1086℃。一方，六方晶系の結晶の密度は4.23g/cm3と比較的小さく，融点は1116℃である。密度は熱処理のしかたによりやや変わる。融解したものを急冷すると水溶性の非晶質の固体が得られる。水に不溶性のものは酸にも不溶であるが，濃アルカリには徐々に侵される。株式会社平凡社 世界大百科事典 第２版について 情報

説明Germanium oxide also called Germanium dioxide is the oxide of germanium, an inorganic compound, featuring the chemical formula GeO2. It is formed as a passivation layer on pure germanium after exposure to oxygen. Germanium dioxide generally has a low toxicity, but shows severe nephrotoxicity at higher doses. Germanium dioxide is still offered on the market in some questionable miracle therapies. Exposure to high doses of germanium dioxide can lead to germanium poisoning.

使用Germanium oxide can be used in Phosphors, transistors and diodes, infraredtransmitting glass.

純化方法The oxide (GeO2) is usually prepared by hydrolysing redistilled GeCl4 and igniting it in order to remove H2O and chloride. It can be further purified by dissolving in hot H2O (solubility is 4g/L cold) evaporating and drying the residual crystalline solid. When the soluble form (which is produced in H2O at 355o) is heated for 100hours, it is converted to the insoluble form. This form is stable at temperatures up to 1033o, and fusion at 1080o for 4hours causes complete de-vitrification and it reverts to the soluble form. [Müller & Blank J Am Chem Soc 46 2358 1924, Dennis & Laubengayer J Am Chem Soc 47 1945 1925, Laubengayer & Morton J Am Chem Soc 54 2303 1932, Schenk in Handbook of Preparative Inorganic Chemistry (Ed. Brauer) Academic Press Vol I p 706 1963.]