|
Mendipite is a rare mineral that was named in 1939 for the locality where it is found, the Mendip Hills in Somerset, England. It is an oxyhalide of lead with formula Pb3Cl2O2.〔 == Crystal structure == Most references assert that mendipite crystallises in the orthorhombic crystal system, disphenoidal class 2 2 2, meaning that it has three mutually perpendicular axes of twofold symmetry, with space group P212121, meaning that each of these axes is a screw axis.〔〔〔 One reference, however, gives the crystal class as orthorhombic m m m with space group Pnma,〔 which has a higher symmetry. In each case the "P" means that the mineral has a primitive unit cell. Unit cell parameters: * a = 9.52 Å, b = 11.87 Å, c = 5.87 Å, Z = 4〔〔〔 * a = 11.87 Å, b = 5.806 Å, c = 9.48 Å, Z = 4〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Mendipite」の詳細全文を読む スポンサード リンク
|