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Before you download, it is recommended that you register below as CHEAQS user, because then you will be informed about updates and bugs. You can expect two to four emails per year. Of course your email will not be used for anything else.

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The current stable version is CHEAQS Next. In addition to that, a research version is available of the completely new (under development) version, especially designed for 64-bits operating systems. More information below the table. You can download CHEAQS Next by clicking in the table below. Stay tuned (e.g. on Facebook or by registering below).

CHEAQS Next (2015 till now) (click here to download): version 2019.5
Incomplete research version of CHEAQS Next (64-bits): version
CRC 32
CRC 64
Size of setup
1.3 Mb
1.2 Mb
Operating system
Windows XP and higher (incl. Windows 10)
Windows 7 and higher but only if 64-bits
Database document
Click here to download
Click here to download version
Click here to download Click here to download version

I recommend not do download CHEAQS from other sites. Only downloading CHEAQS from here guarantees a secure and up-to-date download. Also, I recommend not to use any other uninstallers than the one included with CHEAQS Next.

Regarding the new 64-bits version: already some time ago I decided I wanted to make a new version of CHEAQS, especially designed for 64-bits systems. The new version includes the MSA-model (Mean Spherical Approximation model). This model is able to predict ion activities at high salt concentrations. Unlike many other available models (which are at best semi-empirical), the MSA-model has a solid theoretical basis. Of course there is always a ‘but’. The ‘but’ here is that at this moment the required derivations are available only for a limited number of ions, but I expect that this number will increase soon. I prefer to invest in a method with a solid theoretical basis than in a method that will never become more than semi-empirical. I am grateful to Prof. Jean-Pierre Simonin (CNRS, Paris, France) who developed this model and helped me with the implementation in CHEAQS. Together we prepared a paper that was recently accepted.

It will take some time before this new version is complete. However, you can get a sneak-preview by downloading the ‘research-version’ from the table above; it contains all the elements needed to run the MSA-model. This is ‘work in progress’ and not yet a stable version.