1918 NOTES
Inorganic Chemistry
individual measurements do not follow a temperaturedependent trend and, therefore. should be considered as experimental errors and not significant i n terms of ;L change in a configurational equilibrium. In conclusion, the constant value of the dipole moments measured in solution over the given temperature range in addition to published4 infrared and Raman spectra and high-temperature ninr studies seem to provide strong evidence for a cis-cis (11) configurational equilibrium in solution.
Using KClF,, conversions from 1 to 25% have been observed. The lowest conversion mas observed at XO", while a t 150' a consistent conversion of lo%, \.vas noted. Higher conversions were obtained with CsClF: and ranged from 25 to 90%. 'CYith both salts, however, pure C1Fs was the only condensable gaseous product. Chlorine pentafluoride is a typical interhalogell fluoride in that i t is a corrosive, highly oxidizing substance. It is colorless in the gas phase, water white in the liquid phase, and freezes to a white solid. Vapor pressures were measured on the range -79.0 to +2ao and are fitted to the equation log P,, = 7.2683 1137,16/T('K). Measured vapor pressures at the noted temperatures are [T ('C), P (mm)]: -79.2, CONTRIBUTION FROM THE CHEMISTRY RESEARCH SECTIOS, 16.5; -63.2, 55.0; -50.0, 128.0; -46.3, 166.0; -35, 290.0; -26.2, 463.5; -23.7, 507; -17.9, 634.5; ROCKETDYNE, h n I V I S I O N O F NORTH A M E R I C A N A V I A T I O N , I N C . , CANOCA PARK,CALIFORNIA91304 -14.5, 734.5; -0.2, 1293; +24.8, 2855. The normal boiling point is -14.0' and the melting point is -103 4'. The derived Trouton constant of Chlorine Pentafluoride. 21.8 shows ClFj to be a nonassociated liquid. The Preparation and Properties density of C1FS was measured in the range of -80 to - 23'. The density-temperature relationship of d (g/ BY D. PILIPOVICH, W. MAYA, E. A . LAWTON, H. F. BAUER ml) = 2.696 - (3.08 X 10-3T("K))is derived from the D. F. SHEEHAN, E.N. OGIMACHI,R. D. WILSOY, measured values ("C, g/ml): -80, 2.100; -57, F. C. GUNDERLOY, JR., ASD 1'~ E. BEDWELL 2.0361; -23, 1.922. Received A p r z l l O , 1967 The thermal stability of C1Fj is somewhat less than that of CIF1. The equilibrium Three communications reporting the synthesis of ClFE e ClFi + FP CIFj have appeared. 1--3 This halogen fluoride has been under independent investigation in the Rocketdyne was found to be established fairly readily above 165' laboratories, and we wish now to report on some of our and has been studied in detaiLG work in this area. Chlorine pentafluoride was first Chlorine pentafluoride was smoothly reduced by prepared in low yields in our laboratories by reacburning with ammonia to give a mixture of NH,Cl tions of Fz with chlorine and chlorine-containing comand NH4F. hIultiple analyses of the combustion pounds in a glow discharge a t -196'. Despite the products gave an F/C1 ratio of 4.92. These agreed very small quantities of CIFs isolated, we established closely with chromatographic assays, using the techthe fact that Clz and Fz were sufficient for its formation nique of Lysyj and NewtonjGwhich showed the presand inferred its structure from the infrared spectrum ence of small quantities of Clz. The molecular weight subsequently published by Begun, et d 4 Molecular was determined from the vapor density and was found weights determined from vapor density measurements to be 128 (calcd, 130.5). of impure C1F6also inferred the composition. The high-resolution FI9 nmr spectrum for CIFj has IVhat we believe to be the most useful laboratory been recorded using a Varian DP-60 spectrometer preparation of ClFj involves the fluorination of an operating a t 56.4 Mc. The spectrum was obtained alkali metal chlorotetrafluoride, MC1F4. Those exon a 50 mole yo solution of C1Fs in CFC1,. Two band amined include KClFd, RbClFd, and CsClF4. Alstructures were noted in the nmr spectrum. A strong though all salts yielded ClF: upon fluorination, the doublet was recorded a t -247 ppm (relative to CFC13) cesium and potassium salts were investigated more and a weak quintet a t -4-12 ppm. The coupling conextensively in this study. The general reaction for the stant for the band structures is J = 130 cps. The salt fluorination is seven-component F19 spectrum recorded confirms the hlClFa + Fz +MF + ClFs (1) CdVsymmetry deduced from infrared and Raman studi e ~ . ~ From the above equation i t is seen that only one conA stable mass-cracking pattern for ClFj has been obdensable gaseous product should be obtained. This was tained with a CEC 21-103 C mass spectrometer. Obconfirmed repeatedly by experiment; i.e., pure CIFj served ions, excluding C137isotopes, with the relative n as obtained in these reactions. abundance were [mle, ion, abundance (yo) 1: 111, The conversions of MClF4 to C1Fj were variable. ClFd+, 82.0; 92, ClF8+, 18.6; 73, ClF1+, 100.0; 54, (1) D. F. Smith, Science, 140, 889 (1963). ClF+, 21.0; 46, ClF3'+, 3.5; 37.5, ClF2'+! 0.5; 35, Cl+, (2) E. Gatti, K. L.Krieger, J. R . Sicre, and H. J. Schnmacher, J . I n o v g . Nucl. Chem., 28, 655 (1965). (3) F. P. Gortsens and R. H. Toeniskoetter, I i i u v g . Chem., 5 , 1925 (1966). (4) G. M . Begun, W. H. Fletcher, and U. F. Smith, J . Chrm. Phys., 42, 2236 (1965).
( 5 ) H. F. Bauer and D. F. Sheehan, I n o r g Chem., 6 , 1736 (1967). (6) I. Lysyj and P. I
