EPR spectra differing in hyperfine splitting have been reported for M n(II) ions in V,iV-Dimethylformamide (DMF) when using Mn(C104) 2 and MnCl2 . The difference in the reported spectra is shown to be due to the species MnCl420 by a mole ratio plot. The presence of MnCl® is also indicated by a mole ratio plot. Three basic spectra, differing in hyperfine splitting, are obtained for solutions of Mn (C104) 2 in DMF to which varying amounts of chloride ion have been added. A H 0 for the equilibrium reaction of the species Mn2® und MnCl® was determined from the variation of the formation constant, K c , with temperature over the range 25° to 116 °C. Values for AF° and Zl5° at 25 °C are also given.M n (II) -chloro com plexes have been studied p re viously in aqueous solutions by spectrophotom etric 1, anion exchange 2, cation exchange 3, refractom e tric 4, p o la ro g ra p h ic 5, and E P R 6 m ethods, in w ater-alcohol m ixed solvents by EPR and ion-exch a n g e7, and in aceto nitrile, p ro p an e d io l-1,2-car b o nate and trim ethylp hosphate by spectrophotom etric, potentiom etric, and co n d u c to m e tric 8 m e thods. T he use of EPR spectroscopy to study ionic com plexes in solution has not been so widely used as oth er form s of ab so rp tio n spectroscopy, but is a useful technique fo r the study of com plex fo rm a tion involving tra n sitio n m etal ions since EPR spec tra are o btainable only fo r substances containing u n p aired electrons. Few studies of this n ature in n onaqueous solvents have been rep o rted , although S w a n s o n and L a u r i e 9 have investigated Iro n (III)-chloro com plexes by EPR in a n u m b er of organic solvents including A^/V -D im ethylform am ide (D M F ).C h a n , F u n g and L u t j e 10 have investigated M n (II) com plexes including chloro com plexes in aceto-* Presented at 23rd Southwest American Chemical Society Meeting, Little Rode, Arkansas, December, 1967. ** Present Address: VA Hospital, Kansas City, Mo 1 a) J. A. I b e r s and N. D a v i d s o n , J. Amer. chem. Soc. 72. 4744 [1950]; b) R. J. H. C l a r k and T . M . D u n n , J. diem. Soc. [London] 1963, 1198. 2 K . A. K r a u s and G. E. M o o r e , J. Amer. diem. Soc. 75, 1460 [1953]. 3 D. F. C. M o r r is and E. L. S h o r t , J. c h em . S o c . [London] 1961, 5148. 4 A. Y a . D e i c h , Zhur. Neorg. Khim. 3, 2420 [1958]. 5 S. T r ib a l a t and J. M. C a l d e r o , C . R. hebd. Seances Acad. Sei. 255,925 [1964]. 6 R. G. H a y e s and R. J. M y e r s , J. diem. Physics 40, 877 [1964]. n itrile while L e v a n o n an d L u z 11 have studied these com plexes in m ethanol. The E P R spectrum of M n (II) ions in several nonaqueous solvents inclu d in g D M F has been the subject of two recent p u b lic a tio n s 12,13. In th eir study of the electron spin relax atio n in solvated M n (II) ions in D M F an d dim ethylsulf oxide (D M SO ), using M n(C 104) 2 , G a r r e t t an d M o r g a n 12 rep o rted the characteristic six line hyperfine spectrum fo r the M n (II) ion. L o h m a n n et a l. 13using M nC...