larger than either the alcoholysis of decaborane with methanol alone or the reaction of iodine in methanol with hydrogen, it can be concluded that iodine in methanol solution reacts with boron-boron and boron-hydrogen bonds. The tact that part of the available hydrogen is evolvd in the molecular form suggests that two d8erent types of hydrogen are present. The two
moles of hydrogen evolved in an open system further suggest that these are derived from bridge hydrogen atoms present in the compound. It may thus be possibIe to differentiate chemically between bridge and nonbridge hydrogen in boron hydrides. ARTHURE. MESSNEal Callery Chemical CO., Callery, Pa.
I Present ad-, Eseo Reeearch and En ineering Co.,,P. 0. Box 61, Linden,
N.3.
LITERATURE CITED (1) BescheU, H. C., Meeker, T. R., J. Am. C b n , Soc. 78,1796 (1966). (2) Qutar G.'A., Schaeffer, 0. W., fbid., 78,3646 (1950).
~ P ~ C N V E for D review June 13, 1957. Accepted January 8, 195%
is(cyclope nta d isnyl)Zircon iurn Dichloride H. B, BRADLEY and L. G. DOWELL, Linde Co., Division of Union Carbide Corp., Tonawanda, N. Y.
Structural Formula of Bis(cyc1opentadieny1)Zirconium Dichloride Figure 1. Crystals of bis(cycl0pentadieny1)zirconium dichloride
IS(CSCLOPEST.\DIF:S\.L)~IRCOSIUII
DrcHLoRt1)s (1, 2) is sohb!e in benzcnc, chloroforni, iiiitl dimethyl Cellosolve. It is spsriiiply P O I U I J I ~ in pctrolcum cthcr. I t rfis+olvt.s and
Table I.
Principal lines in X-Ray Spectrum d
Ill0
slon'iy dcco~nposcs in nnter. Polymorphis~nhns not bccn observed.
0.67 5.90 5.67
1 .00 0.52
CIlliSTAL hIORPH0LOC~Y
5.60
4,64 4.61 3.94 3.88 3.76 3.72 3.46 3.33 3.28 3.18 2.996 2,843 2.797 2 749 2,725 2% 608 2.058 2.483 2.434 2 398 2.353 I
I
2.288
2.257 2.221
dl
0.57 0.78 0.05 0.40 0.07 0.05 0,08 0 09
0.Oi
0.03 0.02 0.07 0 .o:! 0.12 0.02 0.00 0.12 0.03 0.04 0.34
0.00 0.08 0.04 0.02 0.05 0.05
AWALWCAL CHEMISTRY
Crystnl systcin, Noiwclinic, Form and Ilnbit. Crystnllixcs from benzenr in rrctnngril:ir tablrta with truncated cdgcs, prcF(wcd oricn tntion (010) (see Figurc 1).
X-RAYDIFFRACTIOS DATA Ccll Dimcnsions. n = 6.20 A,; b = 6.58 A.; ,c,= 13,33A; @ = SDOD'. Formula I%cights prr cell. 2. Formula Wciglit. 202.24. Density. l.iS2 (pycnometer); 1.785 (x-ray). OPTICAL PROPERTIES LY Y
Rcfrnctive IndiceR. (Diryliglit filkr) 1.708 f 03lO5, fl = 1.712 d= 0,005, = 1.76 I13 0.01.
Optic-$&-Angle. (Rcd filtrr) 3 2V = 21 , (Blue filtcr) = 21' = 43O, (Dtiylight filter) = 21' = 31". Dispcrsion, 1' > r, Optic Axinl Plunc, 10% '
Sign of Doublc Refraction. Positive
.A.critc Biscctrix. BXa parallel to b. Estinction. a A c = 13' (daylight
filtcr). JrolccuInr refraction. AIW X n% -I/ nb 2 X l / d = 80.6. Fusion Dntn. Melts nt 232' c. with subliinntion to givc euhedm! crystals (010) on cover law, The refractive indes of thc me% is 1.555 d= 0.008 a t the melting tempcmture.
+
ACKNOWLEDGMENT
The sample of bis(cycIopentndieny1) zirconium dichloride was prepared by J. C. Brantley and E. L. Morehouse of this laboratory. LIYERATURE CITED ( I ) Wilkinson, O., Birmingham, J, hl,, J . A n t . Chon. Sot. 76, 4281 (1054).
(2) Wilkinson, CI., Cotton, F. A,, Chem. and Ind. (London)XBM, 307,
COHTIUBUTIONS of crwh~logrsplriadata for thia section ahould be sent tp W. 6. McCrone, 500 East 33rd SL, Chitxigo 1% Ill.
