Cyclotetrasiloxane, octamethyl-

• Formula: C₈H₂₄O₄Si₄
• Molecular weight: 296.6158
• IUPAC Standard InChI: InChI=1S/C8H24O4Si4/c1-13(2)9-14(3,4)11-16(7,8)12-15(5,6)10-13/h1-8H3 Copy

  
• IUPAC Standard InChIKey: HMMGMWAXVFQUOA-UHFFFAOYSA-N Copy
• CAS Registry Number: 556-67-2
• Chemical structure:
  This structure is also available as a 2d Mol file or as a computed 3d SD file
  The 3d structure may be viewed using Java or Javascript.
• Other names: Oktamethylcyklotetrasiloxan; NUC Silicone VS 7207; CO9810; O9810; Octamethyltetrasiloxane; Octamethylcyclotetrasiloxane; Cyclotetrasilane, octamethyl
• Permanent link for this species. Use this link for bookmarking this species for future reference.
• Information on this page:
  • Phase change data
  • References
  • Notes
• Other data available:
  • IR Spectrum
  • Mass spectrum (electron ionization)
  • Gas Chromatography
• Data at other public NIST sites:
  • Gas Phase Kinetics Database
• Options:
  • Switch to calorie-based units

Data at NIST subscription sites:

• NIST / TRC Web Thermo Tables, professional edition (thermophysical and thermochemical data)

NIST subscription sites provide data under the NIST Standard Reference Data Program, but require an annual fee to access. The purpose of the fee is to recover costs associated with the development of data collections included in such sites. Your institution may already be a subscriber. Follow the links above to find out more about the data in these sites and their terms of usage.

Phase change data

Go To: Top, References, Notes

Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Data compiled as indicated in comments:
BS - Robert L. Brown and Stephen E. Stein
TRC - Thermodynamics Research Center, NIST Boulder Laboratories, Chris Muzny director
AC - William E. Acree, Jr., James S. Chickos

Enthalpy of vaporization

Antoine Equation Parameters

log₁₀(P) = A − (B / (T + C))
    P = vapor pressure (bar)
    T = temperature (K)

View plot Requires a JavaScript / HTML 5 canvas capable browser.

Enthalpy of fusion

References

Go To: Top, Phase change data, Notes

Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

PCR Inc., 1990
PCR Inc., Research Chemicals Catalog 1990-1991, PCR Inc., Gainesville, FL, 1990, 1. [all data]

Myers and Clever, 1969
Myers, R.S.; Clever, H.L., Surface Tension of Octamethylcyclotetrasiloxane and Hexamethyldisilazane and Their Solutions with Carbon Tetrachloride and n-Hexadecane, J. Chem. Eng. Data, 1969, 14, 161-164. [all data]

Alvik and Dale, 1971
Alvik, T.; Dale, J., On the Lack of Conformational Preferences for Cyclic Dimethylsiloxane Oligomers., Acta Chem. Scand., 1971, 25, 2131, https://doi.org/10.3891/acta.chem.scand.25-2131 . [all data]

Marsh, 1968
Marsh, K.N., Thermodynamics of Octamethylcyclotetrasiloxane mixtures, Trans. Faraday Soc., 1968, 64, 883. [all data]

Osthoff, Grubb, et al., 1953
Osthoff, R.C.; Grubb, W.T.; Burkhard, C.A., Physical Properties of organosilicon compounds. I. Hexamethylcyclotrisiloxane and Octamethylcyclotetrasiloxane, J. Am. Chem. Soc., 1953, 75, 2227-9. [all data]

Mekhtiev and Karasharli, 1981
Mekhtiev, S.A.; Karasharli, K.A., Analysis of the results of thermodynamic studies of a series of organosilicon compounds, Azerb. Khim. Zhur., 1981, (5), 85-88. [all data]

McLure and Neville, 1982
McLure, I.A.; Neville, J.F., The critical temperatures and pressures of hexamethyldisilmethylene, octamethylcyclotetrasiloxane, and decamethylcyclpentasiloxane, J. Chem. Thermodyn., 1982, 14, 385-8. [all data]

Young, 1972
Young, C.L., Equilibrium properties of octamethylcyclotetrasiloxane near its critical point and applicability of the principle of corresponding states, J. Chem. Thermodyn., 1972, 4, 65. [all data]

Voronkov, Klyuchnikov, et al., 1991
Voronkov, M.G.; Klyuchnikov, V.A.; Mironenko, E.V.; Shvets, G.N.; Danilova, T.F.; Khudobin, Yu.I., Thermochemistry of organosilicon compounds, Journal of Organometallic Chemistry, 1991, 406, 1-2, 91-97, https://doi.org/10.1016/0022-328X(91)83174-3 . [all data]

Osthoff and Grubb, 1954
Osthoff, Robert C.; Grubb, W.T., Physical Properties of Organosilicon Compounds. III. Thermodynamic Properties of Octamethylcyclotetrasiloxane, J. Am. Chem. Soc., 1954, 76, 2, 399-401, https://doi.org/10.1021/ja01631a025 . [all data]

Flaningam, 1986
Flaningam, Ora L., Vapor pressures of poly(dimethylsiloxane) oligomers, J. Chem. Eng. Data, 1986, 31, 3, 266-272, https://doi.org/10.1021/je00045a002 . [all data]

Ditsent, Skorokhodov, et al., 1971
Ditsent, V.E.; Skorokhodov, I.I.; Terent'eva, N.A.; Zolotareva, M.N., Russ. J. Phys. Chem., 1971, 45, 6, 901. [all data]

Domalski and Hearing, 1996
Domalski, Eugene S.; Hearing, Elizabeth D., Heat Capacities and Entropies of Organic Compounds in the Condensed Phase. Volume III, J. Phys. Chem. Ref. Data, 1996, 25, 1, 1, https://doi.org/10.1063/1.555985 . [all data]

Mekhtiev, Karasharli, et al., 1975
Mekhtiev, S.A.; Karasharli, K.A.; Dzhafarov, O.I., The true heat capacity of 1,1,3,3,5,5-hexamethyl-7,7-diphenylcyclotetrasiloxane in the temperature range 13 to 320 K, Zhur. Fiz. Khim., 1975, 49, 259. [all data]

Alvik, Dale, et al., 1971
Alvik, Thor; Dale, Johannes; Fernholt, L.; Hedberg, Kenneth; Schaumburg, Kjeld; Ehrenberg, L., On the Lack of Conformational Preferences for Cyclic Dimethylsiloxane Oligomers., Acta Chem. Scand., 1971, 25, 2131-2141, https://doi.org/10.3891/acta.chem.scand.25-2131 . [all data]

Notes

Go To: Top, Phase change data, References

• Symbols used in this document:
  

  Pc	Critical pressure
  Tboil	Boiling point
  Tc	Critical temperature
  Tfus	Fusion (melting) point
  Ttriple	Triple point temperature
  Vc	Critical volume
  ΔfusH	Enthalpy of fusion
  ΔvapH	Enthalpy of vaporization
  ΔvapH°	Enthalpy of vaporization at standard conditions
  ρc	Critical density

• Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
• The National Institute of Standards and Technology (NIST) uses its best efforts to deliver a high quality copy of the Database and to verify that the data contained therein have been selected on the basis of sound scientific judgment. However, NIST makes no warranties to that effect, and NIST shall not be liable for any damage that may result from errors or omissions in the Database.
• Customer support for NIST Standard Reference Data products.