Abstract
Various modifications of manganese dioxide have been discussed in terms of the chemical analysis by differential heating curve. The transformation temperatures of the modifications were observed as follows; ${\alpha}-\;and\;{\beta}-MnO_2$ are both $580^{\circ}C∼650^{\circ}C$, ${\gamma}-MnO_2$is is $405^{\circ}C~605^{\circ}C$ and ${\delta}-MnO_2$is $860^{\circ}C~875^{\circ}C$, respectively. Endothermic peaks appeared at the transformation temperatures mentioned above. The restoration temperatures of transformation is completed depending on the amounts of the given samples, but the temperatures of the top of endothermic peaks are nearly constant. The curves of ${\alpha}-,{\beta}-MnO_2$and ${\delta}-MnO_2$ show small peaks while that of ${\gamma}-MnO_2$ shows a sharp and broad peak.
示差熱曲線으로 二酸化망간의 各變態를 分析化學的인 面에서 檢討하였다. 各變態의 轉移溫度는 ${\alpha},{\beta}-MnO_2$인 경우 $580^{\circ}C∼650^{\circ}C$였고, ${\gamma}-MnO_2$인 경우 $405^{\circ}C~605^{\circ}C$, ${\delta}-MnO_2$인 경우 $860^{\circ}C~875^{\circ}C$였으며 吸熱 peak를 나타냈다. 轉移가 完結되는 회복點의 溫度는 試料의 量에 따라서 달랐으나 $T_{max}$點의 溫度는 거의 一定하였다. peak의 모양은 ${\alpha},{\beta}-MnO_2$ 및 ${\gamma}-MnO_2$는 작고 완만하였으며 ${\delta}-MnO_2$는 크고 예민하였다.