SYNTHESIS AND CHEMICAL CHARACTERIZATION OF THE HEXANUCLEAR ANIONS [IR6(CO)14X]- (X=CL, BR, I, OR SCN) - CRYSTAL AND MOLECULAR-STRUCTURES OF [PPH4][IR6(MU-CO)2(CO)12(MU-BR)] AND [N(PPH3)2][IR6(MU-CO)2(CO)12(MU-X)] (X=I OR SCN)