Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

The formation of cubic ice under conditions relevant to Earth's atmosphere


An important mechanism for ice cloud formation in the Earth's atmosphere is homogeneous nucleation of ice in aqueous droplets, and this process is generally assumed to produce hexagonal ice1,2. However, there are some reports that the metastable crystalline phase of ice, cubic ice, may form in the Earth's atmosphere3,4,5. Here we present laboratory experiments demonstrating that cubic ice forms when micrometre-sized droplets of pure water and aqueous solutions freeze homogeneously at cooling rates approaching those found in the atmosphere. We find that the formation of cubic ice is dominant when droplets freeze at temperatures below 190 K, which is in the temperature range relevant for polar stratospheric clouds and clouds in the tropical tropopause region. These results, together with heat transfer calculations, suggest that cubic ice will form in the Earth's atmosphere. If there were a significant fraction of cubic ice in some cold clouds this could increase their water vapour pressure, and modify their microphysics and ice particle size distributions5. Under specific conditions this may lead to enhanced dehydration of the tropopause region5.

This is a preview of subscription content, access via your institution

Relevant articles

Open Access articles citing this article.

Access options

Rent or buy this article

Prices vary by article type



Prices may be subject to local taxes which are calculated during checkout

Figure 1: X-ray diffraction patterns of frozen aqueous droplets.
Figure 2: The intensity ratio, I44/I40, as a function of freezing temperature and concentration of aqueous droplets.


  1. Young, K. C. Microphysical Processes in Clouds (Oxford Univ. Press, New York, 1993)

    Google Scholar 

  2. Pruppacher, H. R. & Klett, J. D. Microphysics of Clouds and Precipitation (Kluwer, Dordrecht, 1997)

    Google Scholar 

  3. Whalley, E. Scheiner's halo: evidence for ice Ic in the atmosphere. Science 211, 389–390 (1981)

    Article  ADS  CAS  Google Scholar 

  4. Riikonen, M. et al. Halo observations provide evidence of airborne cubic ice in the Earth's atmosphere. Appl. Opt. 39, 6080–6085 (2000)

    Article  ADS  CAS  Google Scholar 

  5. Murphy, D. M. Dehydration in cold clouds is enhanced by a transition from cubic to hexagonal ice. Geophys. Res. Lett. 30, doi:10.1029/2003GL018566 (2003)

  6. Peter, T. Microphysics and heterogeneous chemistry of polar stratospheric clouds. Annu. Rev. Phys. Chem. 48, 785–822 (1997)

    Article  ADS  CAS  Google Scholar 

  7. Baker, M. B. Cloud microphysics and climate. Science 276, 1072–1078 (1997)

    Article  CAS  Google Scholar 

  8. DeMott, P. J. in Cirrus (eds Lynch, D. K., Sassen, K., Starr, D. C. & Stephens, G.) 102–135 (Oxford Univ. Press, New York, 2002)

    Google Scholar 

  9. Kohl, I., Mayer, E. & Hallbrucker, A. The glassy water-cubic ice system: a comparative study by X-ray diffraction and differential scanning calorimetry. Phys. Chem. Chem. Phys. 2, 1579–1586 (2000)

    Article  CAS  Google Scholar 

  10. Mayer, E. & Hallbrucker, A. Cubic ice from liquid water. Nature 325, 601–602 (1987)

    Article  ADS  CAS  Google Scholar 

  11. Huang, J. F. & Bartell, L. S. Kinetics of homogeneous nucleation in the freezing of large water clusters. J. Phys. Chem. 99, 3924–3931 (1995)

    Article  CAS  Google Scholar 

  12. Lepault, J., Bigot, D., Studer, D. & Erk, I. Freezing of aqueous specimens: an X-ray diffraction study. J. Microsc. 187, 158–166 (1997)

    Article  CAS  Google Scholar 

  13. Dowell, L. G., Moline, S. W. & Rinfret, A. P. A low-temperature X-ray diffraction study of ice structure formed in aqueous gelatin gels. Biochim. Biophys. Acta 59, 158–167 (1962)

    Article  CAS  Google Scholar 

  14. Dowell, L. G. & Rinfret, A. P. Low-temperature forms of ice as studied by X-ray diffraction. Nature 188, 1144–1148 (1960)

    Article  ADS  CAS  Google Scholar 

  15. Jenniskens, P. & Blake, D. F. Structural transitions in amorphous water ice and astrophysical implications. Science 265, 753–756 (1994)

    Article  ADS  CAS  Google Scholar 

  16. Steytler, D. C., Dore, J. C. & Wright, C. J. Neutron diffraction study of cubic ice nucleation in a porous silica network. J. Phys. Chem. 87, 2458–2459 (1983)

    Article  CAS  Google Scholar 

  17. Takahashi, T. On the role of cubic structure in ice nucleation. J. Cryst. Growth 59, 441–449 (1982)

    Article  ADS  CAS  Google Scholar 

  18. Kiefte, H., Clouter, M. J. & Whalley, E. Cubic ice, snowflakes, and rare-gas solids: surface energy, entropy, and the stability of small crystals. J. Chem. Phys. 81, 1419–1420 (1984)

    Article  ADS  CAS  Google Scholar 

  19. Svishchev, I. M. & Kusalik, P. G. Crystallization of liquid water in a molecular dynamics simulation. Phys. Rev. Lett. 73, 975–978 (1994)

    Article  ADS  CAS  Google Scholar 

  20. Yamada, M., Mossa, S., Stanley, H. E. & Sciortino, F. Interplay between time-temperature transformation and the liquid-liquid phase transition in water. Phys. Rev. Lett. 88, 195701 (2002)

    Article  ADS  Google Scholar 

  21. McClune, W. F. Powder Diffraction File-2 (The International Centre for Diffraction Data, Newtown Square, 2002)

    Google Scholar 

  22. Kuhs, W. F., Bliss, D. V. & Finney, J. L. High-resolution neutron powder diffraction study of ice-Ic. J. Phys. Colloq. 48, 631–636 (1987)

    Google Scholar 

  23. Eidelman, N., Azoury, R. & Sarig, S. Reversal of trends in impurity effects on crystallization parameters. J. Cryst. Growth 74, 1–9 (1986)

    Article  ADS  CAS  Google Scholar 

  24. Murray, B. J. & Plane, J. M. C. The uptake of atomic oxygen on ice films: Implications for noctilucent clouds. Phys. Chem. Chem. Phys. 5, 4129–4138 (2003)

    Article  CAS  Google Scholar 

  25. Ostwald, W. Studien über die Bildung und Umwandlung fester Körper. Z. Phys. Chem. 22, 289–330 (1897)

    CAS  Google Scholar 

  26. Gao, R. S. et al. Evidence that nitric acid increases relative humidity in low-temperature cirrus clouds. Science 303, 516–520 (2004)

    Article  ADS  CAS  Google Scholar 

  27. Chang, H. Y. A., Koop, T., Molina, L. T. & Molina, M. J. Phase transitions in emulsified HNO3/H2O and HNO3/H2SO4/H2O solutions. J. Phys. Chem. A 103, 2673–2679 (1999)

    Article  CAS  Google Scholar 

  28. Koop, T., Kapilashrami, A., Molina, L. T. & Molina, M. J. Phase transitions of sea-salt/water mixtures at low temperatures: Implications for ozone chemistry in the polar marine boundary layer. J. Geophys. Res. 105, 26393–26402 (2000)

    Article  ADS  CAS  Google Scholar 

  29. Bertram, A. K., Koop, T., Molina, L. T. & Molina, M. J. Ice formation in (NH4)2SO4-H2O particles. J. Phys. Chem. A 104, 584–588 (2000)

    Article  CAS  Google Scholar 

  30. Koop, T., Luo, B. P., Tsias, A. & Peter, T. Water activity as the determinant for homogeneous ice nucleation in aqueous solutions. Nature 406, 611–614 (2000)

    Article  ADS  CAS  Google Scholar 

Download references


We thank D. M. Murphy for several helpful discussions on cubic ice, G. N. Patey for discussions on theoretical calculations, and A. Lam and B. Patrick for their assistance with X-ray diffraction measurements and interpretation. We are also grateful to M. Raudsepp for discussions on crystallography. This research was supported by the Canadian Foundation for Climate and Atmospheric Sciences, the Natural Sciences and Engineering Research Council of Canada, and the Canadian Foundation for Innovation.

Author information

Authors and Affiliations


Corresponding author

Correspondence to Allan K. Bertram.

Ethics declarations

Competing interests

The authors declare that they have no competing financial interests.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Murray, B., Knopf, D. & Bertram, A. The formation of cubic ice under conditions relevant to Earth's atmosphere. Nature 434, 202–205 (2005).

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI:

This article is cited by


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing