P. H. Bird and M. G. H. Wallbridge, J. Chem. SOC., 1965, 3923. H. I. Schlesinger, R. T. Sanderson, and A. B. Burg, J. Amer. Chem. SOC.1, 940, 62, 3421. R. A. Ogg and J. D. Ray, Discuss. Favaday SOC., 1955, 19, 239. L. Banford and G. E. Coates, J . Chem. SOC.1, 964, 5591. L. Taylor, U.S. Dept. Comm., Office Tech. Serv., 1961, A.D., 256, 887, pp. 30-32. W. C. Price, J. Chem. Phys., 1949, 17, 1044. Nakamoto, " Infrared Spectra of Inorganic and Coordination Compounds," Wiley, New York, 1963, sect., 111-1. D. R. Schultz and R. W. Parry, J . Amer. Chem. SOC.1,9 58, 80, 4. S. G. Shore and R. W. Parry, J . Amer. Chem. SOC.1,9 58, 80, 8. W. L. Taylor, E. Griswold, and J. Kleinberg, J. Amer. Chem. SOC., 1942, 64, 316. R. L. Gertis, R. E. Dickerson, and J. L. Brown, Inorg. Chem., 1964, 3, 872. P. H. Bird and 31. G. H. Wallbridge, Chenz. Comm., 1965, 291. G. W. Frazer, N. N. Greenwood, and B. P. Straughan, J. Chem. Soc., 1963, 3472. A. R. Emery and R. C. Taylor, Spectrochim. Ada, 1960, 16, 1455. W. Klemm and E. Tanke, 2. anorg. Chew,., 1931, 200, 343. S. G. Shore and R. W. Parry, J. Amer. Chem. SOC., 1955, 77, 6084. N. N. Greenwood, E. J. F. Ross, and A. Storr, J , Chem. SOC., 1965, 1400. S. Ahrland, J. Chatt, and N. R. Davies, Quart. Rev., 1958, 12, 265. N. A. Bailey, P. H. Bird, and M. G. H. Wallbridge, Chem. Comnz., 1966, 286. L. Pauling, " The Nature of the Chemical Bond," Cornell Univ. Press, Ithaca, 1960, p. 224.