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6181
libria; Prentice-Hall, Inc.: Englewocd Cliffs, NJ, 1969. (27) Barton, A. F. M. In CRC Handbook of Solubility Parameiers and Other Cohesion Parameters; CRC Press, Inc.: Boca Raton, FL, 1983. (28) Fletcher, A. N. J . Phys. Chem. 1972, 76, 2562-2571. (29) Fletcher, A. N.; Heller, C. A. J . Phys. Chem. 1967, 71, 3742-3756. (30) Symons, M. C. R.; Thomas, V. J . Chem. SOC.,Faraday Trans. I 1981, 77, 1883-1890. (31) Herndon, W. C.; Vincenti, S.P . J. J . Am. Chem. SOC.1983, 105, 6 174-6 175. (32) Barnes, A. J.; Hallam, H. E.; Jones, D. Proc. R. Soc. London, A 1973, 335,97-111. (33) (a) Krueger, P. J.; Mettee, H. D. Can. J . Chem. 1964, 42, 347. (b) Krueger, P. J.; Mettee, H. D. Can. J . Chem. 1964, 42, 326. (c) Krueger, P. J.; Mettee, H. D. Can. J . Chem. 1964, 42, 340. (34) Barnes, A. J.; Murto, J. J . Chem. SOC.,Faraday Trans. 2 1972,68, 1642. (35) Chitale, S. M.; Jose, C. I. J. Chem. Soc., Faraday Trans. 1 1986,82, 663. (36) Kirkwood, J. G. J . Chem. Phys. 1934, 2, 351. (37) Bauer, E.; Magat, M. J . Phys. Radium 1938, 9, 319. (38) Conrad, M. P.; Straws, H. L. J . Phys. Chem. 1987,91, 1668-1673. (39) Scherer, J. R. In Advances in Infrared and Raman Spectroscopy; Clark, R. J. H., Hater, R. E., Eds.; Heyden & Sons: Philadelphia, PA, 1978; pp 149-216. (40) Maciejewski, A. Chem. Phys. Lett. 1989, 163, 81. (41) Guillory, W. A. Introduction to Molecular Spectroscopy; Allyn and Bacon, Inc.: Boston, MA, 1977. (42) Leickman, J. C.; Guissani, Y.; Bratos, S.J . Chem. Phys. 1978, 68, 3380-3390. (43) Gordon, R. G. J . Chem. Phys. 1966, 44, 1830-1836. (44) (a) Thompson, H. W.; Temple, R. B. J . Chem. SOC.1948, 1422. (b) Thompson, H. W.; Temple, R. B. J. Chem. SOC.1948, 1432. (45) Lewis, A.; Pace, E. L. J. Chem. Phys. 1973, 58, 3661-3668.
(10) Hoffman, H.; Kalus, J.; Thurn, H. Prog. Colloid Polym. Sci. 1983, 261, 1043. (11) Liebman, J. F. In Fluorine-Containing Molecules; Liebman, J. F., Greenberg, A., Dolbier, W. R., Eds.; VCH Publishers: New York, 1988; pp 309-328. (12) Scott, R. L. J . Phys. Chem. 1958,62, 136-145. (13) Y e , G. G.; Fulton, J. L.; Smith, R. D. Langmuir 1992,8,377-384. (14) Aveyard, R.; Briscoe, B. J.; Chapman, J. J. Chem. SOC.,Faraday Trans. I 1973,69, 1772-1778. (15) Pacynko, W. F.; Yanvood, J.; Tiddy, G.J. T. J . Chem. SOC.,Faraday Trans. 1 1989,85 (6), 1397-1407. (16) Perrin, D. D.; Armarego, W. L. F. In Purification of Laboratory Chemicals, 3rd ed.; Pergamon Press: New York, 1988; pp 16-17. (1 7) Weissberger,A., Ed. In Techniques of Organic Chemistry, vol. 3, part 1. Separation and Purification, 2nd ed.; Interscience Publishers, Inc.: New York, 1956; p 787. (18) Skoog, D. A.; West, D. M. In Fundamentals of Analytical Chemistry, 3rd ed.:Holt. Rinehart. & Winston: New York. 1976: D 607. (19)Kolthoff, I. M:; Belcher, R.; Stenger, V. A.;.Matsuyama, G. In Volumetric Analysis; Interscience Publishers, Inc.: New York, 1957; Vol. 3. (20) Yee, G. G.;Fulton, J. L.; Blitz, J. P.; Smith, R. D. J . Phys. Chem. 1991, 95, 1403-1409. (21) Besserer, G. J.; Robinson, D. B. J . Chem. Eng. Data 1973, 18, 137-140. (22) Gas Encyclopaedia; Elsevier: New York, 1976. (23) Younglove, B. A.; Ely, J. F. J . Phys. Chem. Ref. Data 1987, 16, 577-798. (24) Edwards, H. G. M.; Farwell, D. W. J . Mol. Struct. 1990, 220, 2 17-226. (25) Gurdial, G.S.;Foster, N. R.; Yun, J. S. L. In Proceedings of the 2nd
Iniernational Symposium on Supercritical Fluids; McHugh, M. A., Ed.; Johns Hopkins University: Baltimore, MD, 1991; pp 66-69. (26) Prausnitz, J. M. Molecular Thermodynamics of Fluid Phase Equi-
Infrared Spectra of GeS, SGeS, SGeO, and OGeO in Solid Argon Paniz Hassanzadeh and Lester Andrews* Department of Chemistry, University of Virginia, Charlottesville, Virginia 22901 (Received: December 26, 1991; In Final Form: March 24, 1992)
New germanium sulfides, oxides, and mixed sulfide-oxides were prepared from the reaction of elemental sulfur with elemental germanium and oxygen and characterized by infrared absorption spectroscopy. The GeS diatomic product showed absorptions at 564.6, 566.8,568.1, 569.2, and 571.7 cm-' for natural isotopic germanium. At higher sulfur concentrations SGeS revealed absorptions at 649.3,653.3,655.4,657.5, and 661.8 cm-l for the v3 fundamental. The Ge-0 vibration in SGeO was observed as a weak band with germanium isotopic components at 981.5, 984.3, 985.8, 987.3, and 990.4 an-'. The v3 fundamental of Ge02 exhibited new bands at 1048.2, 1052.3, 1054.5, 1056.7, and 1061.3 cm-I. Sulfur and oxygen isotopic absorptions confirmed the above assignments.
Introduction The silicon oxide and sulfide molecules have been investigated extensively;'-1° following carbon dioxide and disulfide, silicon dioxide and disulfide are linear molecules.IO The GeO diatomic is well-known, but Ge02 has only been characterized in nitrogen matrix reaction^.^ Among germanium sulfides, only GeS has been studied extensively by electronic emi~sion,'~J~ micr~wave,'~J~ infrared emission,'* and matrix infraredkgspectroscopic techniques. An absorption band at 566.6 cm-l has been assigned to the most abundant isotope of germanium sulfide (74Ge32S)in solid argon,Ig and a brief report of natural isotopic GeS2in solid argon has appeared.20 Reagent seeded microwave discharges were employed to form germanium sulfides in order to obtain sulfur isotopic substitution. This work reports the fundamental frequencies for all stable isotopes of germanium and sulfur and confirms the previous GeS and GeS2 assignments. In addition, infrared absorption spectra of SGeO and OGeO in solid argon are featured.
Experimental Section The vacuum system and chamber for matrix-isolation studies have been described previously?' A closedcycle refrigerator (CTI 0022-365419212096-6181$03.00/0
Cryogenics, Model 22) and an indicator/controller were used to cool and monitor the temperature of the CsI window. FTIR spectra were recorded on a Nicolet 60SXR at 0.5-cm-I resolution (KBr beam splitter) and fO.1-cm-' frequency accuracy for observed bands with 1.O-cm-' full-width at half-absorbance maximum. Natural isotopic germanium (Aesar), germane (Matheson), natural sulfur (Electronic Space Products, Inc.; recrystallized), enriched sulfur-34 material with 85% 34S (Cambridge Isotope Laboratories), natural oxygen gas (Matheson), and 97% enriched oxygen-18 (YEDA) were used as received. The quartz tubes for discharge reactions have been described previously.21-22A discharge tube was modified by adding a constriction in the cavity region to hold a small piece of elemental germanium, as shown in Figure 1. The discharged gas stream was condensed on a CsI window at 12 f 1 K,and FTIR spectra were recorded before and after annealing.
Results Matrix infrared spectroscopic results for several different reagent combinations will be presented. Germane + Sulfur. An argon discharge was generated within the inner tube of a coaxial discharge tube and extended all the
0 1992 American Chemical Society
6182 The Journal of Physical Chemistry, Vol. 96, No. 15, 1992
AI
I
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Hassanzadeh and Andrews
I
Os -.' I
irk=
THERMOCOUPLE
A
I
RESERVOIR HEATER
Figure 1. Modified coaxial quartz discharge tube used for reacting germanium, sulfur, and oxygen in microwave-powered argon discharge. TABLE I: Observed Infrared Absorption B8nds (cm-I) for Germanium W d e and Oxide Isotopes in Solid Argon 76Ge34S 552.8" (551.8Ib 32S76Ge180 939.0 555.1 (554.2j 942.0 556.4 (3 943.4 557.5 (556.5) 945.1 560.0 (559.1) 948.5 564.6 (563.6) 981.3 566.8 (565.8) 984.0 568.1 (-) 985.5 569.2 (568.1) 987.0 57 1.7 (570.7) 990.1 638.9 981.5 642.9 984.3 645.0 985.8 647.2 987.3 651.6 990.4 644.4 1006.8 1011.1 648.4 1013.4 650.5 1015.7 652.5 1020.4 656.9 1030.3 649.3 1034.4 653.3 1036.6 655.4 657.5 1038.8 661.8 1043.3 1048.2 923.6 (-) 1052.3 926.0 (929.8) 1054.5 927.3 (-1 1056.7 928.4 (932.2) 1061.3 931.0 (934.8) 969.0 (-) 971.1 (975.3) 972.3 (-) 973.4 (977.6) 976.0 (98 1.5)
(-1 (947.5)
(-1
(949.0) (952.6) (-)
(988.3)
(3
(991.3) (994.4) (-)
(988.7) (-)
(991.7) (994.8)
580
570
560
550
Wavenumber F i i 2. Infrared spectra in the 550-580-cm-l region for natural isotopic germaniumsulfur discharge products trapped in solid argon at 12 f 1 K (a) natural isotopic sulfur, (b) 85% enriched sulfur-34, (c) 50% mixed sulfur-32/sulfur-34.
"Major site indicated by arrows in figures. bMatrix site splittings given in parentheses.
way to the tip of the outer tube. A sulfur reservoir temperature of 90 O C gave a purplish blue discharge, and small amount of S3 and S4 was formed on the cold window. When a slow stream of pure germane was passad through the outer tube, an intense green color indicative of phosphorescence from GeS (a3n X'Z) excited by the microwave discharge irradiation was observed on the cold window.I5 An excellent yield of GeS was produced; however, due to the spectral interferences from GeH, (812 cm-I), GezHd(749 cm-I), and their dissociation prod~cts,2~ this method was abandoned. In order to reduce these spectral interferences, a 2% mixture of GeH,/Ar was used as the discharge gas and sent through the inner discharge tube. Shortly after the discharge was initiated, a layer of germanium was formed inside the inner tube before the microwave cavity region, which did not allow reaction with sulfur. Gemdm + Sulfur. In order to prevent spectral interferences from germane and to take advantage of the relatively higher temperature within the inner discharge tube, which is inside the outer tube jacket, a clean piece of pure germanium was placed
-
in the inner discharge tube on the microwave cavity axis, as shown in Figure 1. The argon discharge was initiated, the sulfur reservoir was heated, and an appreciable amount of GeS and other germanium sulfides were formed on the cold window. Due to the relatively higher product yield and lack of spectral interferences from germanium hydrides, this method was employed for the remaining experiments. The sulfur reservoir temperature was adjusted to around 80 "C such that only a small amount of S3 and S4 was observed. It was also found necessary to carry out the reaction and deposition for about 12 h to accumulate enough product for infrared spectral studies. The observed absorption bands in the region from 500 to 1100 cm-' are collected in Table I. Similar experiments were also run with 85% and 50% enriched isotopic sulfur-34. Each of the bands in the 564.6-, 566.8-, 568.1-, 569.2-, and 571.7-cm-' series showed a doublet isotopic pattern with the 50% enriched isotopic sulfur-34, as shown in Figure 2. These bands revealed matrix sites at lower frequencies which increased upon annealing to 28 f 2 K and decreased above this temperature. Each of the bands in the 649.3-, 653.3-, 655.4, 6575, and 661.8-cm-' series showed a 1:2:1 triplet pattern with the 50% enriched isotopic sulfur-34, as shown in Figure 3. No matrix site was observed for these series of absorption bands. Germanium Sulfur Oxygen. In another experiment, a coaxial discharge tube was used and a 1%mixture of oxygen/argon was introduced through the outer tube into the discharge. Besides GeO bandsg at 969.0, 971.1, 972.3,973.4, and 976.0 cm-I, a series of new absorption bands at 981.5,984.3,985.8,987.3, and 990.4 cm-I and another series at 1048.2, 1052.3, 1054.5, 1056.7, and 1061.3 cm-I were observed. The 981-990-cm-' bands showed a shift of less than 0.5 cm-' to lower frequencies with the sulfur-34 and a doublet pattern with the 50% enriched isotopic oxygen-18,
+
+
Infrared Spectra of GeS, SGeS, SGeO, and OGeO in Ar(s)
''SGe3'S 3
I
665
655
645
635
Wavenumber
Figure 3. Infrared spectra in the 635-665-cm-' region for natural isotopic germaniumsulfur discharge products trapped in solid argon at 12 1 K (a) natural isotopic sulfur, (b) 85% enriched sulfur-34, (c) 50% mixed
sulfur-32/sulfur-34.
as shown in Figure 4. These bands also revealed matrix sites which were favored on annealing to 20 f 2 K and vanished after annealing at 30 f 2 K. In another experiment, a 1% mixture of O2in argon was deposited with the laser ablated6 germanium for 6 h; only the GeO bands and the 1048-1061-cm~'bands were observed. The series of bands at 1048-1061 cm-' showed a triplet 1:2:1 isotopic pattern and the 981-990-cm-l bands showed a doublet isotopic pattern with 50% enriched isotopic oxygen, as is shown in Figure 4. In another experiment, a mixture of H2/02/Ar = 1/1/10 was passed through the outer coaxial discharge tube; however, the intensities of the previously observed band were not changed, and no new bands were observed.
Discussions The new molecules characterized by isotopic substitution and annealing behavior will be discussed in turn. Ces, The series of bands at 564.6, 566.8, 568.1, 569.2, and 571.7 cm-l are formed from the reaction of Ge with sulfur in all experiments. These bands showed the pentet pattern characteristic of the natural distribution (0.205/0.274/0.078/0.365/0.078) for the five stable germanium isotopes (70/72/73/74/76) and a doublet pattern with 50% enriched isotopic sulfur indicative of a molecule with one sulfur atom. The isotopic ratios for germanium (R72/74 = 569.2/566.8 = 1.0042) with sulfur-32and sulfur (R32 34 = 566.8/555.1 = 1.0211) with germanium-74 are in excehent agreement with the values of R72-32/7&32 = 1.0042 and R7&32/74-34= 1.0212 calculated for a Ge-S harmonic oscillator. These absorptions are also in agreement with the previously reported bands produced from the Knudsen cell evaporation of a
The Journal of Physical Chemistry, Vole96, NO. 15, 1992 6183 molten mixture of germanium and sulfur.l* The argon matrix fundamental for 7%3e32Sat 566.6 cm-l is 5.6 cm-l red-shifted from the 572.2-cm-' gas-phase value.l7 A similar red matrix shift was observed for the SiS diatomic in solid argon.22 The series of absorptions at 563.6, 565.8,568.1, and 570.7 cm-l, which grow on annealing at 28 f 2 K and vanish on further annealing at 35 f 2 K, show intensity ratios in agreement with the natural abundance for 76Ge,7%3e,72Ge, and 70Ge. These bands exhibit the same germanium and sulfur isotopic ratios as GeS. Thus, these absorption bands are attributed to diatomic GeS molecules trapped in different matrix sites or perturbed by a nearby species. SGeS. The series of absorptions at 649.3,653.3,655.4, 657.5, and 661.8 cm-'were observed only after a long period of deposition and when the sulfur vapor was in excess. These bands show intensity ratios in agreement with the natural abundance of germanium isotopes, which indicates a single germanium atom species. Each of these bands also showed a triplet (1:2:1) isotopic pattern with 50% enriched isotopic sulfur, which indicated two equivalent sulfur atoms in this new species. The germanium isotopic ratio of R72/74 = 657.5/653.3 = 1.0064 with sulfur-32 is slightly higher than the value calculated for the diatomic Ge-S harmonic oscillator (R72-32 74-32 = 1.0042), while the sulfur isotopic ratio of R32/34 = 653.31d42.9 = 1.0162 with germanium-74 is slightly lower than the value calculated for the diatomic Ge-S harmonic oscillator (R74-32 74-34 = 1.0210). These isotopic ratios suggest an antisymmetric b e - S vibrational motion for a linear molecule. Valence angles can be calculated for C , molecules from isotopic frequency ratios.2u4,25Central isotopic substitution reveals a lower limit to the valence angle, while terminal isotopic substitution gives an upper limit owing to anharmonicity effects.25 Three isotopic pairs of germanium-72/germanium-74, germanium-70lgermawith sulfur-32 give nium-72, and germanium-70/germanium-74 an average cosine of -0.956 while the three germanium isotopes with sulfur-32/sulfur-34 give an average cosine of -1.002. These isotopic v3 fundamental calculations for GeS2 clearly indicate a linear molecule. A similar conclusion has been reached for Sis2*10,21
The present identificationof GeS2as a product of the elemental reaction in an argon discharge is in agreement with a very recent matrix photolysis study of natural OCS in the presence of GeS20 The presence of the CO byproduct in the matrix had no effect on the observed frequencies, which for the 5 natural germanium isotopic disulfides ranged between 0.10 and 0.16 cm-l higher than values obtained in the present discharge work. The agreement is certainly within the experimental error. The assignment v3 of GeS, enables the symmetry coordinate force constant for the antisymmetric stretch, F33 = F, - F,,, to be determined as 4.31 mdyn/A (F, is the force constant for stretching the Ge-S bond in the triatomic GeS, molecule, and F, is the stretch-stretch interaction force constant). Without the v 1 fundamental, the interaction force constant (F,) cannot be determined; however, a reasonable estimate of F,, can be made. In the case of C 0 2 and CS2, F,, is 8% of Fr.26 F,, for GeS2 is probably less than 8% but greater than 0% of Fr,I0 If we take F,, at 4 f 2% of F, as an estimate, then F, = 4.5 f 0.2 and F,, = 0.2 f 0.1 and the Raman active fundamental for GeS, is predicted at 500 f 20 cm-l. The force constant for GeS, obtained from the observed GeS isotopic data, is 4.22 mdyn/A, which is slightly smaller than the F, value for GeS2 for any positive value of Frr.This is also the case for SiS and SiS,; the force constant for 28Si32Sis 4.80 mdyn/A based on a 739.1-cm-1 fundamental, and the F, - F, value for SiS2 is 4.83 mdyn/A based on v3 = 917.9 cm-1.10-21 Such is, however, not the case for CO/C02 and CS/CS2 where the diatomic force constant is slightly larger.10-26 OCeS. The 981-990-cm-' bands were produced when oxygen was added to the germanium sulfide emerging from the innei tube of the coaxial discharge and are in the Ge-O vibrational region. They showed a relative intensity pattern in agreement with the natural abundance of germanium isotopes. The calculated isotopic
6184 The Journal of Physical Chemistry, Vol. 96, No. 15, 1992
Hassanzadeh and Andrews
1 1 1
i
e B
2
b
a I
I
1070
1055
I
1040
1025
I
1010
I
995
I
8
980
965
950
I
I
I
935
920
905
Wavenumber
Figure 4. Infrared spe&a in the 905-1070-cm-I region for natural isotopic germanium-sulfur-enriched isotopic oxygen discharge products trapped in solid argon at 12 f 1 K: (a) natural isotopic oxygen, (b) 97% enriched oxygen-18, (c) 50% enriched oxygen-18, (d) spectrum (c) after annealing at 25 f 2 K and recooling to 12 f 1 K.
ratios for sulfur and oxygen for harmonic oscillators Ge-S and Ge-0 are 1.0042 and 1.0492, respectively. The observed small sulfur isotopic ratio of R32/M= 984.3/984.0 = 1.0003 and higher oxygen isotopic ratio of R16/18= 984.3/942.0 = 1,0449 indicate that the absorption has more Ge-0 stretching character than Ge-S. Mixed isotopic sulfur and oxygen showed doublet patterns suggesting that there is one sulfur and one oxygen atom in this species. This series of germanium isotopic bands is assigned to the Ge-0 stretching vibration in OGeS. The Ge-S stretching vibration of this species is expected to be relatively weaker in the Ge-S stretching region (500-700 cm-*) and was not observed. OCeO. The series of bands at 1048.2, 1052.3, 1054.5, 1056.7, and 1061.3 cm-l did not show any sulfur isotopic shift and were also observed in the absence of sulfur in the reaction of oxygen with laser ablated germanium atoms. These bands showed a relative intensity pattern in agreement with the natural abundance of germanium isotopes and a triplet (1:2:1) isotopic pattern with 50% enriched isotopic oxygen, which indicates the presence of two equivalent oxygen atoms and one germanium atom. The germanium isotopic ratio of R72/74= 1056.7/1052.3 = 1.0042 with oxygen-16 is slightly higher than the value of R7>.16/79-16 = 1.0025 calculated for harmonic oscillator Ge-0, while the oxygen isotopic ratio of R16/18= 1052.3/1011.1 = 1.0407 with germanium-74 is slightly lower than the value calculated for harmonic oscillator Ge-0 as expected for an antisymmetric stretching vibration for linear "symmetric Ge02. These bands are assigned to the u3 fundamental of OGeO, which is also in agreement with the bands previously observed from nitrogen matrix studies7and the reaction of laser evaporated germanium with oxygen.27 Valence angle cosine calculations were also done for Ge02 The lighter oxygen atoms provided for greater anharmonicity in the u3 vibration than the heavier sulfur atoms; hence the upper limit-lower limit cosine spread was larger. Three germanium isotopic pairs with oxygen-16 gave cosine values of -0.995, -0.977, and
TABLE E Force Constants (mdyn/A) for Group 14 Oxide rad SuKdes"
0 and S O2 and S2 compds
compds
F. CO
cs
Si0 SiS GeO GeS
18.44 8.35 9.00 4.80 7.30 4.22
C02 CS2 SiOl SiS2 GeO2 GeS2
F,
F,
F,,
15.51 7.54 9.2 f 0.4 5.0 f 0.2 7.6 f 0.2 4.5 i 0.2
1.33 0.59 0.4 f 0.2 0.2 f 0.1 0.3 f 0.1 0.2 f 0.1
14.18 6.95
8.82 4.83 7.28 4.31
F, is the bond stretching force constant; F, is the stretch-stretch interaction force constant; F,, is the antisymmetric symmetry coordinate force constant. -0.986, whereas isotopic oxygen pairs with three germanium isotopes gave m i n e values of -1.068, -1.083, and -1.082. These
values bracket the limiting value and indicate a linear structure for GeOz. The symmetry coordinate force constant F3,= F,- F, for Ge02 is 7.28 mdyn/A, which is slightly smaller than F,for GeO at 7.30 mdyn/A. If we approximate F, at 4 2% of F,for Ge02, then F, = 7.6 & 0.2 and F, = 0.3 0.1. and u1 is estimated to be 920 f 20 an-'.A similar calculation for SiO/Si021-5 is also included in the Table 11. Trends in Croup 14 Oxide and SIIWde Force Comtants. Comparisons of force constants in Table I1 calculated from matrix data whenever possible show an interesting reversal in the trend of diatomic bond stretching force constant larger than triatomic from C to Si and Ge. Granted some estimate of stretch-stretch interaction force constant is required, and the approximation F, = 4% of F,used in Table I1 is reasonable. Even if F, = 0, which
*
*
J. Phys. Chem. 1992,96,6185-6188 is a clear underestimate, the F, for GeS is less than for GeS2. Schnockel and Koppe pointed out that the difference between triple and double bonds was less for silicon than for carbon compounds and suggested that this difference would decrease with Ge and Sn compounds.10 The present work supports this trend. The G e 4 and Ge-S stretching force constants are larger for the triatomic species (classical double bonds) than for the diatomic molecules (classical triple bonds). This all indica- that u bonding is weak with heavier elements and that terminology developed for carbon is not generally applicable to the heavier membcrs of the group 14 family. COddOM
The new molecules SGeS, SGeO, and OGeO were produced from the reaction of elemental germanium, sulfur, and oxygen in an argon discharge and trapped in solid argon for infrared absorption studies. Germanium, sulfur, and oxygen isotopic shifts substantiated assignment of the 649-662- and 1048-1061-cm-l bands to the antisymmetric stretching vibrations of SGeS and OGeO, respectively, and predicted linear structure for these molecules. Isotopic shifts also identified the mixed sulfideoxide SGeO in the 981-990-cm-' region. Force constants for the triatomic oxides and sulfides are larger than for the diatomic molecules in the case of germanium, which is a reversal of the case with carbon. This further underscores the trend of diminishing difference between molecules where double and triple bonds are expected based on the precedent set by carbon and shows that u bonding is less important in the heavier group 14 diatomics.
Acknowledgment. We gratefully acknowledge financial support from NSF Grant CHE 88-20764. Regbtry No. GeS, 12025-32-0; GeS2, 12025-34-2; SGeO, 14184804-6; Ge02, 1310-53-8; Ar, 7440-37-1.
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References rad Notes (1) Schnockel, H. Angew. Chem., Inr. Ed. Engl. 1978, 17, 616. (2) Schnockel, H. 2.Anorg. Allg. Chem. 1980,460, 37. (3) Anderson, J. S.; Ogden, J. S . J. Chem. Phys. 1969,51, 4189. (4) Hastie, J. W.; Hauge, R. H.; Margrave, J. L. Inorg. Chim. Acra 1969, 3, 601. ( 5 ) Schnockel, H. Angew. Chem. 1978,90, 638. (6) McCluskey, M.; Andrews, A. J. Phys. Chem. 1991, 95, 3545. (7) Boz, A.; Ogden, J. S.;Orgee, L. J . Phys. Chem. 1974, 78, 1763. (8) Ogden, J. S.;Ricks, M. J. J . Chem. Phys. 1970, 52, 352. (9) Withnall, R.; Andrews, L. J. Phys. Chem. 1990, 94, 2351. (IO) Schnockel, H.; Koppe, R. J . Am. Chem. Soc. 1989, 111,4583. ( I 1) Shapiro, C. V.; Gibbs, G. C.; Laubengayer, A. V. Phys. Reu. 1932, 40, 354. (12) Barrow, R. F. Proc. Phys. Soc., London 1941,53, 116. (13) Drummond. G.; Barrow, R. F. Proc. Phys. Soc., London 1937,49, 543. (14) Meyer, B.; Jones, Y.;Smith, J. J. J. Mol. Spectrosc. 1971,37, 100. (15) Meyer, B.; Smith, J. J.; Spitzer, K. J . Chem. Phys. 1970,53, 3616. (16) Hoeft, J.; Lovas, F. J.; Tiemann, E.; Tischer, R.; Torring, T. 2. Naturforsch. 1969, 240, 1217. (17) Stieda, W. U.; Tiemann, E.; Torring, T.; Hoeft, J. 2.Narurforsch. 1976,310, 374. (18) Uehara, H.; Horiai, K.; Susoka, K.; Nakagawa, K. Chem. Phys. L a . 1989, 160, 149. (19) Marino, Ch. P.; Guerin, J. P.; Nixon, E. R. J . Mol. Specfrosc. 1974, 51, 160. (20) Koppe, R.; Schnockel, H. J. Mol. Srrucr. 1990, 238,429. (21) Mielke, Z.; Brabon, G. D.; Andrews, L. J. Phys. Chem. 1991, 95, 75. The 1:2:1 isotopic triplet at 917.9, 913.9, and 909.7 cm-I with 50% sulfur-34 confirms the identification of SiS2 (22) Brabon, G. D.; Mielke, Z.; Andrews, L. J . Phys. Chem. 1991, 95, 79. (23) Smith, G. R.; Guillory, W. A. J . Chem. Phys. 1972,56, 1423. (24) Andrews, A,; Spiker, R. C., Jr. J . Phys. Chem. 1972, 76, 3208. (25) Allavena, M.; Rysnik, R.; White, D.; Calder, V.; Mann, D. E. J. Chem. Phys. 1969, 50, 3399. (26) Henberg, G. Infrared and Raman Spectra of Polyaromic Molecules; Van Nostrand: Princeton, NJ, 1945. (27) Andrews, L.; McClusky, M. J. Mol. Spectrosc., in press.
Molecular Interactions with Icy Surfaces: Infrared Spectra of CO Absorbed in Microporous Amorphous Ice J. Paul Devlin Department of Chemistry, Oklahoma State University, Stillwater, Oklahoma 74078 (Received: January 8, 1992)
Spectroscopic effects produced by small mijlecules absorbed within the micropores of amorphous ice have been examined for ethylene oxide, CF,, and carbon monoxide in an effort to characterize the interaction of CO with the ice surface. The absorption of CO at temperatures above 28 K produces a large shift (44 cm-') in the position of the infrared bands of the dangling OH bonds at the pore surfaces and results in two distinct stretching-modebands for the carbon monoxide, with one of the bands having an unusually high-frequency position (2152 cm-I). The influence of the absorbed small ether, ethylene oxide, was predictable as the dangling-bond bands of the ice "disappear", presumably because of an H-bond interaction with the absorbed ether. Because of this blocking of the dangling groups, the absorption of carbon monoxide into amorphous ice containing preabsorbed ethylene oxide (17%) occurs without interaction with the dangling bonds. Since the band at 2152 cm-' is very weak in this case, it is assigned to CO bonded to the dangling OH groups. This assignment is supported by the observation that coabsorption with the hydrophobic gas CF4,which has only a minor influence on the spectrum of the dangling OH groups and which is expected to cause preferential association of coabsorbed CO with the dangling OH groups, enhances the relative intensity of the 2152-cm-' band.
introductioa
Several aspects of the surface of ice have been revealed in recent theoretical and experimental studies of ice clusters and microporous amorphous ice.'-' In particular, through a combination of simulation' and spectroscopic results? it has been established that dangling OH group are abundant at the surfaces of both crystalline and amorphous ice. Further, these nonbonded groups are present throughout films of vapor deposited amorphous ice, presumably on the walls of the pores of what has been charac-
terized, through gas adsorption studies, as a permeable microporous substance." Two narrow infrared absorption bands in the non-H-bonded region of the ice spectra have been assigned to dangling O H groups of surface H 2 0 molecules, either 2- or 3-coordinated with other water molecules.' Exposure of the microporous ice to small molecules results in their ready uptake, provided the molecules are mobile at the temperature of the ice substrate.' The relative strength of the interactions of the small molecules with the dangling OH bonds,
0022-3654/92/2096-6185$03.00/0Q 1992 American Chemical Society
