Feb 16, 2009
Earlier this year Laura Haddad of Haddad|Drugan emailed me with an unusual request regarding crystal structures. But, before I tell you about that, here’s a little background. Laura is working on an artistic installation called “Undercurrents”, that will be the basis of the public art component of a stormwater treatment facility on Seattle’s Elliott Bay.
The first phase has been in place since 2003 and includes a plaza and integrated sculpture, designed by Haddad. The concept reveals invisible site functions based around, in Laura’s words, “A poetically etched stainless steel swale in the paving channels surface drainage into Elliott Bay, mimicking the actions of the underground outfall pipes.”
The second phase of this project is now under construction and includes a new mechanical vault wrapped on three sides with a planted sculpted earth berm, conceptually conveying the message that a stormwater utility should be treated as green infrastructure. “The fourth side of this berm is a stainless steel retaining wall etched with a metaphoric pictogram depicting the processes of stormwater collection, transport, and treatment,” Laura told me. “Five gigantic mirrored stainless steel vent pipes extend out of the vault. Their reflections of the surrounding sky and landscape convey a concept of infrastructure merging with its environment.”
It all sounds quite wonderful, especially given the otherwise utilitarian nature of such a facility and their more common lack of aesthetics. Apparently Construction will be complete in August 2009, and so Laura was on a tight deadline when she emailed me.
Could I furnish her with molecular structures for two water treatment chemicals – sodium hypochlorite and sodium bisulfite? The idea would be to create a collage of chemicals showing how NaOCl is used to “treat” the water and the NaHSO4 used to “neutralize” the NaOCl. Seemed fair enough, I suggested I provide the “molecular” structures for both in various formats (space filling, van der Waals, ball and stick models etc and also generate nice three-dimensional crystal structure diagrams.
Obviously, neither of these compounds can be described as molecular in nature, but my first port of call was ChemSpider.com nevertheless, with it’s millions of chemical substances I assumed I’d find leads immediately. And, of course, I did. NaOCl and NaSO3 are both listed, but there were no CIF crystal structure files associated with their entries, which was odd. I double-checked with ChemSpiderMan (Tony Williams) who confirmed this, but then things started to get even more confusing.
I had imagined that the crystal structures of these two compounds would feature prominently in X-ray structure resources and so be widely available in a variety of downloadable formats from which Laura and I could work to create a suitable starting point for her steel etchings. But, after an hour or two of search I’d not found cif files or indeed anything related. I spoke to a contact, Noel O’Boyle, who suggested I check with CCDC. Unfortunately, their turnaround time would take me way past Laura’s (and so my) deadline. Noel also pointed out that there is no crystal structure for NaOCl because it does not exist as a solid, according to at least one resource. That would seem to scupper the idea of creating a 3D diagram of its crystal lattice, although another page on that same resource suggested that it does indeed exist as a white solid.
I turned to several other contacts. Sheffield University’s Mark Winter, famous for, among other things his WebElements.com site, pointed me to a clutch of research papers from the 1970s showing various polymorphs of the bisulfite, but no NaOCl, maybe Noel was right. Another good friend, science photographer Dana Lipp suggested I contact the tech services department of Phillips Analytical or some other manufacture of XRD equipment. In the meantime, chemist Venkat Thalladi of Worcester Polytechnic Institute, Massachusetts, by way of Richard Wobbe, sent me a message with an attachment – the CIF file for sodium bisulfite! Unfortunately, he also confirmed that he didn’t think the crystal structure for NaOCl had been confirmed.
At this point, I gave Laura an update on the structure situation. By her own admission, her “brain does not wrap around molecules and chemistry” so she was at my chemical mercy, although she also pointed out that given that it’s art, there is room for artistic licence.
In the end, I provided NaOCl in the various molecular model formats discussed and Laura was very happy to work with those. I also fired up Thalladi’s CIF in Crystal Diamond, tweaking it somewhat to get the most aesthetic layout and then rendering with Pov-ray to produce a shadowed, 3D perspective on the crystal lattice at high resolution, a thumbnail crop from which is shown here.
So, if you’re ever in Seattle’s Elliott Bay and visiting the stormwater treatment facility on a site-seeing tour, do check out Laura’s steely artwork and rest assured that the chemistry is accurate. If you have similar artistic requirements please get in touch. But, more pressingly if you know of a crystal structure for NaOCl do leave a comment