| 摘要 |
PURPOSE:To obtain a superconductor having a higher lattice constant and a high superconductivity transition temp. CONSTITUTION:Ammonia vapor is sealed in a glass tube contg. Na2CsC60 under 1atm pressure and the tube is kept at 0-50 deg.C. Ammonia molecules react with cesium positioned between octahedral lattices of the crystal to give {Cs(NH3)4}<+> and Na2Cs(NH3)4C60 is formed. When the lattice constant is measured by X-ray diffraction, it is increased from 14.130Angstrom of Na2CsC60 to 14.530Angstrom almost equal to the lattice constant of Cs2RbC60. The superconductivity transition temp. of the resultant material is 92K which is about 3 times as high as that of RbCs2 C60. having the almost same lattice constant. |
