B. MOROSIN AND E. C. LINGAFELTER
50
Vol. 65
THE COXFIGURATIOX OF THE TETRACHLOROCUPRATE(I1) ION BY B. NOROSIN AND E. C. LINGAFELTER The Chemistry Department, University of Washington, Seattle, Wash. Recezved A p r d 89, 1960
Further refinement of the crystal structure of C~2CuC14and a partial analysis of the crystal structure of [N(CH3)r]2CuC14 have been Carrie: out. The bond angles in the distorted tetrahedral configuration of CuC14-- are 124.9, 123.3, 102.5 and 102.9", all f0.7
.
In 1952, Helmholx and Kruh' reported the crystal structure of Cs2CuC14. They found the structure to contain discrete CuC14-- ions with a configuration intermediate between tetrahedral and planar, the C1-Cu-Cl bond angles being 104 and 120". Although it is evident that the reported structure is essentially correct, their reported value of
factors were used for Cs, Cu and C1, and McWeeny scattering factors5 for the other atoms.
Refinement of CszCuCb.-Refinement of the projection of CszCuC1( on [OlO] was carried out by difference syntheses t o a value of R = Z 11 Fo 1 1 Fc I/ / Z 1 FO1 = 0.10,'j using individual atom isotropic temperature factors. The final atomic positions and temperature factors are given in Table I, and bond lengths and angles in Table 11. The standard deviation of the Cu-C1 lengths is 0.02 A. prompted us to carry the refinement further and and of the C1-Cu-C1 angles is 0.7", calculated by also to investigate the structure of [N(CH3)4]2- the method of Cruick~hank.~Thus the changes in CuCL2 The similarity between the axial ratio of bond lengths from those of Helmholz and Kruh are CszCuC14,a : b : c = 1.2691:1:1.6137 and of [N- not significant and the changes in bond angles, (CH3)4I2CuCl4,a : b : c = 1.3416: 1: 1.6766 suggest while significant, are small. that their structures are quite similar. TABLE I Experimental POSITION AKD TEMPERATURE PARAMETERS FOR CsnCuCI4 Crystals of both compounds were obtained by evaporation of aqueous solutions containing the stoichiometric proportions of CuC12 and CsCl or N(CHI),Cl. The yellow-orange needles of Cs2CuC14 were sirllilar to those of Helmhols and Kruh' while the yellow-orange crystals of [N(CHa)J2CuC14 were short rod-like prisms bounded by [ O l l ] and terminated by [loo]. Precession and Weis:enberg photographs taken with Cu radiation (A = 1.5418 A.) of the CspCuC14 crystals led to the cell dimensions uo = 9.719, bo = 7.658, co = 12.358 A., all It 0.01 A., in agreement with Helmholz and 1Cruh.l Systematic absences of ( O M ) for h 1 odd and of (hkO) for h odd indicate the space group to be Pnma or Pnala. Similar photographs of the [N(CH&]&uCla crystals led to the celldimensions a. = 36.381, bo = 9.039, co = 15.155 A. (all + 0.01 A.). However, all but a relatively sma!l number cf rather weak reflections could be indexed with au = 12.127 A. Therefore, these weak reflections were ignored in the present treatment and the cell was considered to have a. = 12.127 A. These cell dimensions are in satisfactory agreement with those reported by Mellor.2 Systematic absence of (Okl) for k 1 odd and of (hkO)for h odd indicate the space group to be Pnma or Pn2,a. Integrated photographic intensity data were collected for (hOl) of CszCuC1, with MoKa radiation on a Nonius Integrating Weissenberg camera, for (hkO) of [N(CH,),]?CuCI, with CuKa radiation on the same camera, and for (1:OL) of !K(CHa)412CuC&with MoKa radiation on an integrating precession ame era.^ In all cases multiple films and a series of exposure times were used. Camera integration was in one direction only and each spot was scanned in the other direction with a Moll type densitometer feeding into a Leeds and X9rthrup amplifier and recorder having a logarithmic slide mire. The area under the tracing of each spot was measured with a planimeter and these areas were taken as the relative intensities. Lorente and polarization factors were applied, but no corrections were made for absorption. All calculations were made with an IBM 650 computer. In the calculation of structure factors, Thomas and Umeda4 scattering
+
+
(1) L. Helmholz and R. F. Kruh, J . A m . Chem. Sac., 74, 1176 (1952). (2) D. P. Mellor, 2. Krist., AlO1, 160 (1939). ( 3 ) J. M. Stewart and E. C . Lingafelter, Rev. Sci. Instr., 31, 399 (1960). (-1) L. H. Thomas and K. Umeda, J . Chem. Phys., 26, 293 (1957).
Atom
y/ba
de
B
0.25 .75 .25 .25 .25
0.1018 ,3263 ,4178 ,5745 ,3935 ,3500
3.3 3.1 2.7 3.3 4.3 4.3
d a
CSl cs2 cu e11
0.1317 - ,0065 .2320 .3340 c1, ,0030 e13 .2NO From ref. 1.
0
TABLE I1 BOKDLENGTHS ASD ANGLES IN CuCl,-cu-CI1 cu-c12 cu-e13 Cl&u-CIZ Cl1-CU-C13 c12-cu-cI1 Cldh-Cla'
In CszCuCla
Y I n iN(GHs)41zCuCl~--From r0101 From [ O O l ]
2.18 d. 2.25 2.18 124.9" 102.5 102.9 123.3
2.22 A. 2.20 2.23 129.8' 99.6 102.2 127.1
2.28 d. 2.24 2.23 131.5' 99.4 101.5 127.4
Approximate Structure of [N(CH3)4]2CuC14.Neglecting tjhe faint reflections which indicate the tripling of the a nxis, the several Weissenberg and precession photographs taken of [N(CH3)4]2CuC14 are quite similar t o those of [K(CH3)4]2ZnCl,,* indicating that their structures are similar. Since the (h01)net shows no indication of the 36 8.ao,the effective unitocell in the projection on [OlO] has a0 = 12.127 A. Initial atomic positions were obtained from a Patterson projection P(z,z). Refinement of these positions by Fourier and difference syntheses was carried out to a final value of R = 0.12, using individual atom isotropic temperature factors. and assuming the space group to be Pnam. ( 5 ) R. McWeeny, Aria Cryst.. 4, 513 (1951).
(6) Tables of observed and calculated structure factors for both compounds may be obtained from E. C . Lingafelter. (7) D. W. J. Cruickshank, Acta Cryst., 2 , 65 (1949). (8) B. hforosin and E. C . Lingafelter, ibid., 12, 611 (1959).
SEDIMEXTATION RATEOF SPHERICAL PARTICLES
Jan., 1961
51
Refinement of the projection on [OOlj is expected TABLEI11 to be less satisfactory, since the (hkO) zone shows POSITIONAL AND TEMPERATURE PARAMETERS FOR the faint reflections corresponding to the 36 8. ao. 1N(CHahltC~Clc Neglect of these faint reflections can therefore be -hOE ( R 0.119)7 h k O (R = 0.181)d a Z/C B dc. y/b B expected t o lead to only approximate coordinates. 0.2281 0.4028 3 . 3 0.2281 0.250 5 . 9 Fixing the x coordinates at the values calculated Cu ,0495 .3700 6 . 5 ,0450 .250 6 . 1 from the projection on [OlO], it was found possible Clt .3100 .5320 6 . 5 ,3170 .250 8 . 5 to refine the projection on [OOl] only to R = 0.25. Clz .2750 .3490 9.9 ,2740 ,029 6 . 5 Allowing both x and y coordinates to vary, it was c1, ,1280 .0970 6 . 0 .1280 .250 8.0 found possible t o refine the projection on [OOl] to N1 .5050 .8330 6.0 .5280 .250 8 . 0 R = 0.18, with final x coordinates differing some- Nz ,2590 .1130 8.0 ,2220 .250 8.0 what from those obtained from the projection on C1 .1270 -.0010 8.0 .1270 .250 8 . 0 [OlO]. The final coordinates are given in Table 111. CZ .0770 .1320 9 . 0 .0600 ,121 7 . 0 The differences in x coordinates between the two CO .4210 ,7580 7 . 5 .4210 .250 8.0 projections range from 0 to 0.085 A.,with a mean C4 C S ,4500 .9150 7 . 5 .4500 .250 8.0 value of 0.023 for the heavy atoms, Cu and C1, .5710 .8280 9.0 .5920 .121 7 . 0 and from 0 to 0.45 A., with a mean value of 0.15 A., Ca for the light atoms. It therefore seems apparent angles of 128 and 101'; and in C U C ~ ~ in O~,~~ that the differences between the three sub-cells which the copper ion is surrounded by a set of are primarily in the y-coordinates of the N and C oxygen ions with 0-Cu-0 angles of 122 and 103". atoms. Since our main interest in [N(CH3)4I2CuCl4 The configuration has been quantitatively acis in the configuration of the CuC14--, no further counted for on the basis of ligand field theory for attempts have been made to refine the projection CuC14-- by Felsenfeld. l1 on [OOl] using the faint reflections. Some comment should be made with regard to Using y-coordinates from the projection on [OOl], the values obtained for the atomic temperature x coordinates from the projection on [OlO], and the factors in [N(CH&]ZCUC~~. The large value for two sets of x coordinates, two sets of bond distances Cu for the hkO zone is due to omission of the disand angles in CuC14-- have been calculated and are persion correction as discussed by Stewart, given in Table 11, along with the values from the Breazeale and Lingafelter.I2 The large values for CszCuCle. Beca,use of the uncertainty in the co- C1 may arise from either actual large thermal ordinates, no significance should be attached to the motion or a small randomness of position associated differences between the values from the two com- with the tripling of the small cell. pounds, but it is apparent that the CuC14-- is disThis work was supported in part by the Office of torted from tetra,hedral toward square configuration Ordnance Research (U. S. Army) under Contract No. DA-04-200-ORD-668 and in part by the U. S. as described by Helmholz and Kruh. This intermediate configuration for 4-coordinate Public Health Service under Grant A-2241. Cu(I1) has now been found in three cases: the (10) E. Prince, kbid., 10, 544 (1957). present CuC14---; the CuBrr-- in C S ~ C Uwith B ~ ~ ~ (11) G. Felsenfeld, Proc. Roy. SOC.(London), A236, 506 (1956). 3
w.,
(9) B. Morosin and E. C. Lingafelter, Acta cryst., 13, 807 (1960).
(12) J. M. Stewart, J. D. Breazeale and E. C. Lingafelter, Acta Cryst. (in press).
ON THE VARIATION OF THE SEDIMENTATION RATE OF SPHERICAL PARTICLES WITH COSCENTRATIOX BY A. G. OG.STOX Department of Phg.rica1 Biochemistry, John Curtin School of Medical Research, Australian National University, Canberra A.C.T. Received May 3, 1960
The resulk of Cheng and Schachman' on dynamic properties of suspensions of uniform polystyrene latex particles are used to test the theory for the concentration dependence of sedimentation rate, based by Fessler and Ogston2 and Ogstona on the treatment of Sullivan and Herte14 of the flow of fluid through a porous plug.
Fessler and Ogston2 and Ogston3 showed that, obtained by this treatment for a variety of types with certain assumptions, Sullivan and Hertel's4 of solute particles were in reasonable agreement with treatment of the flow of fluid through alporous plug what were believed to be the weights, shapes and can be applied to the sedimentation of solute parti- hydrodynamic volumes of these particles. Howcles a t finite concentration through a fluid medium. ever, it has not so far been possible to apply this Ogston3 showed that the particle characteristics treatment to any material whose particle characteristics are certainly and accurately known from (1) P. T. Cheng and H. K. Schachman, J . Polymer Sci., 16, 19 (1955). independent evidence. (2) J. H. Fessler and A. G. Ogston, Trans. Faraday Soc., 47, 667 The measurements of Cheng and Schachmanl on (1951). a suspension of polystyrene latex particles make (3) A. G. Ogston, ;bid., 49, 1481 (1953). such a test possible. These particles are known by (4) R. R. Sullivan and K. L. Hertel, Adv. ColZoid Sei., 1, 37 (1942).
