Inorganic Ch’emistry
1012 J. R. GEICHMAN, E. A. SMITH, AND P. R. OGLE
tetragonal with the unique axis being some integral diate compounds, NaF*YF3and 5NaF.SYF,.; one is multiple of the pseudo-cubic cell edge, but single-crystal an unidentified metastable compound of probable data are needed to test this hypothesis. Evidence that formula 5NaF.3YF3; the other three include N a F the low-temperature form of 5NaF.9YF3 exists over a and two forms of YFs. Yttrium trifluoride crystalsmall but finite composition range was observed in the lizes from the molten phase in an unknown crystal powder diffraction patterns a t 63.5 and 64 mole % YF3; form which inverts on cooling below 1052’ to the orthorhombic form described by Zalkin and T e m p l e t ~ n . ~ through the temperature interval 710 to 537O, the intensities of the superlattice lines were reduced in proLattice parameters and refractive indices of the cubic portion to the extent that the composition 5NaF 9YFa NaF.YF3-5NaF.SYF3 solid solution crystals are given deviated from the stoichiometric ratio. The primitive in Fig. 2. Inversion of cubic NaFaYF3 crystals results lattice reported by Nowacki5 is very similar to that of in the formation of uniaxial (+) hexagonal crystals the ordered form of 5NaF.9YF3 and, though slightly having refractive indices N , 1.464, N , 1.486, with a = larger in apparent cell size, is not deducible as identical. 5.95 f 0.03 A. and c = 3.52 f 0.03 The calcuThe lattice parameter assigned to the “primitive cubic lated density of these crystals with 1.5 formula weights YF3” observed by Nowacki was 5.655 f 0.003 A. per unit cell is 4.22 g./cc., as compared with a measured Although Zalkin and Templeton inferred that the value of 4.2 g./cc. Because of the similarity of stoiprimitive cubic phase was NaFa3YF3,’ no conclusions chiometry and unit-cell dimensions, the hexagonal can be drawn with respect to the relationship of this phase was deduced to be isostructural with &-Na2ThFe. phase to the ordered form of 5NaF.SYF3 because crysAlthough the powder pattern of the ordered form of tals observed in our study have never exhibited so 5NaFagYF3 can be indexed assuming a primitive cubic large a unit-cell parameter and because quantitative cell with a = 5.530 B.,a larger cell is required by intensity data are not available for comparison. stoichiometry; moreover, a noncubic symmetry is indicated by optical data since the crystals are uniaxial Acknowledgments.-We are indebted to J. H. (-), with N , 1.465, N , 1.478. An explanation conBurns and Hugo Steinfink for their helpful advice re. sistent with these observations is that the unit cell is garding crystal chemistry. In addition, i t is a pleasure (15) J. H. Burns and D. J. Duchamp, “Reactor Chemistry Division to acknowledge the support and encouragement of Annual Progress Report for Period Ending Jan. 31, 1962,” ORNL-3262. W. R. Grimes and other members of the ORKL staff. p. 15. s
CONTRIBUTIOS FROM
THE
GOODYEAR ATOMICCORPORATION, PJKETON, OHIO
Hexafluorides of Molybdenum, Tungsten, and Uranium. 11. Reactions with Nitryl Fluoride, Nitrosyl Fluoride, and Nitrosyl Chloride1s2 BY J. R. GEICHMAN, E. A. SMITH,
AND
P. R. OGLE
Received April 19,1963 Reactions of three metal hexafluorides with nitrosyl and iiitryl fluorides resulted in solid compounds of the composition XO,F. &IF6where x’ is 1 or 2 and M is W, Mo, or U. Infrared absorption data for these compounds indicate that the ionic form N0,+MF7- and the molecular form NO,F.MFs contribute to the structure of the solid. n’itrospl chloride does not act as do the nitrogen oxyfluorides with the hexafluorides but, like nitric oxide,3 it reduces molybdenum and uranium to complex nitrosyl fluorides of M o ( T ) and U(V), with the formation of chlorine. Tungsten hexafluoride does not react with nitrosyl chloride.
Introduction The study of the action of various nitrogen-containing compounds on the hexafluorides of molybdenum, tungsten, and uranium has beeii continued in this laboratory. The action of nitrous oxide and nitric oxide toward the hexafluorides has been reported previously. That work suggested that reaction occurred between the hexafluorides and nitrosyl fluoride. In (1) This work was performed under Contract AT-(33-2)-1 with t h e U. S . Atomic Energy Commission. ( 2 ) Paper presented in part a t t h e 138th National Meeting of the American Chemical Society, New York, N. Y . ,September 14, 1960. (3) J. R. Geichman, E. A . Smith, S. S. Trond, and P. R. Ogle, Inorg. Chem., 1, 661 (1962).
the present investigation the reaction stoichiometry between the hexafluorides and nitryl fluoride, nitrosyl fluoride, or nitrosyl chloride and the physical and chemical properties of the reaction products were determined. Experimental Materials.-Purification of the hexafluorides and nitrosyl fluoride has been d e ~ c r i b e d . Hydrogen ~ fluoride was purified by the method of Jarry and Davis.4 Boron trifluoride was used as obtained commercially from the Matheson Company. Nitryl fluoride was prepared by allowing a slight excess (over (4) R. L. Jarry and W. Davis, J . Phys. Chem., 67, 60 (1953).
HEXAFLUORIDES OF MOLYBDENUM, TUNGSTEN, AND URANIUM 1013
VoZ. 2, No. 5, October, 1963
TABLE I ~"HTSICAI, PROPERTIES O F NO,F.MF& SOLID COMPOUNDS Vap. press. Compound
hTOMOF7
-Wave NO +
2328
numbers, cm. -I----. MFTNO@
640
Color
White
Density, g./cc.a
at Z O O , mm.
3
6
Element
Analyses, Calcd.
%--=--Found
Mo F N W F N
37.05 35.89 51.36 51.92 5.41 5.85 hTOWF7 2330 620 White 3 . 7 f0 . 2 a t 2 5 "
