Characterizations of F-superconductors and selected F-compounds, amorphous carbon, and (VO)2P2O7 by F-19, C-13, H-1, and P-31 NMR, and a new probe for multiple pulse, MAS, and DAS NMR

NMR signals of F-19 were measured in the polycrystalline inorganic conductor Ag2F and in the polycrystalline insulators AgF, YOF, EuOF, YF3, CuF2, BaF2, and KF to compare them to the signals found in the so-called 1-2-3-type compounds with claimed formulas RBa2Cu3O(7-x)F(x) (R = Y and Eu). No evidence for a Knight-shifted, built-in fluorine-signal was found in the 1-2-3-type superconductors. The only signal found was from the BaF2 which is an impurity in the superconductors.