Cyclotrisiloxane, hexamethyl-

• Formula: C₆H₁₈O₃Si₃
• Molecular weight: 222.4618
• IUPAC Standard InChI: InChI=1S/C6H18O3Si3/c1-10(2)7-11(3,4)9-12(5,6)8-10/h1-6H3 Copy

  
• IUPAC Standard InChIKey: HTDJPCNNEPUOOQ-UHFFFAOYSA-N Copy
• CAS Registry Number: 541-05-9
• 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: Dimethylsiloxane cyclic trimer; Hexamethylcyclotrisiloxane; CH7260
• Permanent link for this species. Use this link for bookmarking this species for future reference.
• Information on this page:
  • Condensed phase thermochemistry data
  • 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.

Condensed phase thermochemistry data

Go To: Top, Phase change data, References, Notes

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

Data compiled by: Eugene S. Domalski and Elizabeth D. Hearing

Constant pressure heat capacity of solid

Phase change data

Go To: Top, Condensed phase thermochemistry data, 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
DH - Eugene S. Domalski and Elizabeth D. Hearing

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 sublimation

Enthalpy of fusion

Enthalpy of phase transition

Entropy of phase transition

References

Go To: Top, Condensed phase thermochemistry data, Phase change data, Notes

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

Kuliev, Dzhafarov, et al., 1982
Kuliev, A.M.; Dzhafarov, O.I.; Karasharli, K.A.; Kostryukov, V.N., Heat capacity and thermodynamic functions of cyclic methylphenylsiloxanes, Zhur. Fiz. Khim., 1982, 56, 310-313. [all data]

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

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]

Kuliev, Dzhafarov, et al., 1982, 2
Kuliev, A.M.; Dzhafarov, O.I.; Karasharli, K.A.; Kostryukov, V.N., Heat capacity and thermodynamic functions of cyclic methylphenylsiloxanes, Zh. Fiz. Khim., 1982, 56, 310-13. [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]

Bragin and Karapet'yants, 1974
Bragin, G.P.; Karapet'yants, M.K., Russ. J. Phys. Chem., 1974, 48, 612. [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]

Osthoff, Grubb, et al., 1953, 2
Osthoff, Robert C.; Grubb, W.T.; Burkhard, Charles A., Physical Properties of Organosilicon Compounds. I. Hexamethylcyclotrisiloxane and Octamethylcyclotetrasiloxane, J. Am. Chem. Soc., 1953, 75, 9, 2227-2229, https://doi.org/10.1021/ja01105a060 . [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]

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, Condensed phase thermochemistry data, Phase change data, References

• Symbols used in this document:
  

  Cp,solid	Constant pressure heat capacity of solid
  S°solid,1 bar	Entropy of solid at standard conditions (1 bar)
  Tboil	Boiling point
  Tfus	Fusion (melting) point
  Ttriple	Triple point temperature
  ΔHtrs	Enthalpy of phase transition
  ΔStrs	Entropy of phase transition
  ΔfusH	Enthalpy of fusion
  ΔsubH	Enthalpy of sublimation
  ΔvapH	Enthalpy of vaporization

• 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.