The Rock Blooms
James Nehlsen GS
Department of Chemical Engineering
This unique semi-organic mineral structure is the result of a slow chemical reaction. The reaction occurs spontaneously between alkanethiols, which are simple sulfur-containing organic compounds, and lead oxide. Here, the oxide is a surface coating on a coil of metallic lead wire that forms naturally in moist air. The structure consists of layers of lead alkanethiolates, a stable compound that is solid at room temperature and has a distinct yellow color. The layers grow outwards from the surface of the wire as the reaction proceeds, curling into “petals.” But be careful, beautiful though it may be, this “flower” is toxic. The structure grows slowly upward as the wire is uncoiled by the growing petals, eventually filling the jar in which the reaction occurs. This structure took more than a week to grow. A less delicate but faster growing form of this material can be used to remove polluting sulfur compounds from gasoline during the refining process.