A Very Stable Monomeric Nitrosyldisulfonate Salt Recent research papers describing the structure of potassium nitrosyldisulfonate (Fremy's salt)' and some salts of the violet free radicalion ON(SOda2- with organic cationsPprompt me to draw attention to avery stable compound of this type, which is prepared by seeond-year undergraduates in this department as part of their inorganic chemistry laboratory program. Earlier research work3 on nickel isothiocyanate complexes suggested that the large dipositive organic cation (c-xylylene-bistriphenq.lphosphonium)* (abbreviated to c-catat) might be very effective in stabilizing the monomeric ON(S08)nP-anion, and this proved to be so. Addition of the ealculrtted amount of solid Fremy's salt' to a stirred, aqueous solution of (c-cat)BrE gives an immediate violet precipitate. The compound is apparently quite stable in moist sir. The relatively high cost of (c-cat)Br.for student labaratorypreparations is offset by the high yield (-75y0) whiehuermits the use of small auantitiesof the reactants (in cur promam 0.15 g of (0-cat)Bn are employed). The high iwlevulnr wrlghr d the product prrvenl. kcl.llra1~d~lrrnlinallcmof the ~ R T R I I I I ) K I I P Iwill1 ~ ~ ~ ~t1.e ~ 11Sla1 studrrlr islwrarory nutgnrtw I>nlnnrr~. Ilt,wevrr, the o l a ~ r v ~ t i oofn a n ipr .-ignnl 9 - 1 !UIT 1 1 -IlilJ'C, provides an nltcrnnrive way of d t . r n ~ ~ r a r thepararnagnerim ~ng of the cumpound ~t,itudrntproltps.
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HOTVIE, A. R., GLASSER, L. S. D., AND MOSER,W., J. Chem. Soc. ( A ) ,3043 (1968). FILLMORE, D. L.,AND WILSON,B. J., Znorg Chem., 7,1592 (1968). 8 FORSTER, D., AND GOODGAME, D. M. L.,Zno~g.Chem., 4,823 (1965). 4 PALMER, W. G., "Experimental Inorganic Chemistry," Cambridge University Press, 1954, p. 281. 6 Available from Aldrich Chemical Company, Inc. 1
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IMPERIAL COLLEGE OF SCIENCE AND TECHNOLOGY S.W. 7. ENGLAND LONDON
724 / Journal o f Chemicol Education
