COMPLEX COINAGE METAL(I) THIOSULFATES

 

E. J. Chan, B.W. Skelton and A.H. White

 

University of Western Australia, School of Biomedical and Chemical Sciences,

35 Stirling Hwy, Crawley, W.A. 6009, Australia (eric@crystal.uwa.edu.au)

 

 

Materials crystallized from aqueous solutions of thiosulfates (i.e. Na, K, and NH4) and coinage metal halides, may be relevant to photographic ÔfixationÕ.  Previously known members of the isomorphous, tetragonal I-42d M19M22X2(S2O3)2, M1 = group 1 cation, M2 = (Cu, Ag), series, together with further new members, have been isolated as eight complexes, the nitrates and the potassium/copper adduct all new, containing the complex anion [M2(SSO3)4]7- with quasi tetrahedral S-M-S geometry.  Salts of the form M1(2n-1)M2 (S2O3)n.xH2O, n = 1-3, have also been defined: For n = 3, M2 = Cu, M1/x = K/2.25 or 1 5/6, NH4/6, (and also for the (NH4)4Na/4H2O.MeOH adduct) the arrays take the form M15[Cu(SSO3)3].xS with distorted trigonal planar CuS3 coordination environments; the silver counterparts take the form M110[(O3SS)2Ag(m-SSO3)2Ag(SSO3)2] for M1 = K, NH4.  For n = 2 adducts have only been defined for M2 = Ag, the anions of the M = Na, K adducts being dimeric and polymeric: Na6[(O3SS)2Ag(m-SSO3)2Ag(SSO3)].3H2O, K3[Ag(m-SSO3)2].H2O ; a polymeric copper 1 counterpart of the latter is found in Na5Cu(NO3)2(S2O3)2 = 2NaNO3.Na3[Cu(m-SSO3)2].  For n = 1, NaAgS2O3, isolated as both the known mono and a new anhydrate, exhibit a two dimensional polymeric complex anion in both forms but with different contributing motifs, 6- and 4- membered rings respectively.  (NH4)13Ag3(S2O3)8.2H2O takes the form (NH4)13[{(O3SS)Ag(m-SSO3)2}2Ag], a linear central silver atom linking a pair of [Ag(SSO3)4]7- entities.  In Na6[(O3SS)Ag(m-SSO3)2Ag(SSO3)].3H2O, two binuclear anions are present as single clusters, the associated oxygen atoms disposed to one side, sandwiching layers of sodium ions.