[Pd 2 (η 4 -P 7 ) 2 ] 4− : a Pd 2 sandwiched by two anionic nortricyclane-type polyphosphides

By introducing [Pd(PPh 3 ) 4 ] into a P 7 3− solution, we have successfully synthesized and crystallized [Pd 2 (η 4 -P 7 ) 2 ] 4− (1a) in [Na(crypt-222)] 4 1a.