Ligated transition metal derivatives of heteropolyanions

Salts and acids containing a triheteropolyanion in which one addenda atom of a heterododecatungstate or heterododecamolybdate is replaced by one tin atom or by two germanium atoms, in which the tin atom or the germanium atoms are bonded to a ligated transition metal, the central atom of the heterododecaanion is not bonded directly to the ligated transition metal-tin moiety or the ligated transition metal-germanium moiety, the added ligated transition metal is not part of the dodecanuclear cage structure, the heteropolyanion contains at least one metal-metal bond which is outside the skeletal structure of the heteropolyanion, and the salts and acids are of a formula selected from the group consisting of

• Q.sub.a L.sub.b MSnM'.sub.11 XO.sub.39 ( 1)
• Q.sub.a L.sub.b-1 M(SnM'.sub.11 XO.sub.39).sub.2 ( 2)
• Q.sub.a (L.sub.b MGe).sub.2 M'.sub.11 XO.sub.40 ( 3)
• Q.sub.a L.sub.b M(GeOH).sub.2 M'.sub.11 XO.sub.39 ( 4)
• Q.sub.a L.sub.b M(SnM'.sub.11 XO.sub.39)(SnM".sub.11 X'O.sub.39) (5)
• and
• {Q.sub.a L.sub.b-1 MGe.sub.2 M'.sub.11 XO.sub.40 }.sub.y ( 6)
• in which
• Q is one equivalent of a cation;
• L.sub.b M is a ligated transition metal M bonded to b ligands L, b is at least 1, and the ligands are the same or different when b is greater than 1;
• M' and M" are W or Mo;
• X and X' are Si, P, Co or Ge;
• with the proviso that at least one of M" and X' is different from M' and X, respectively;
• a is the number of formal negative charges on the heteropolyanion;
• and
• y is the degree of polymerization.