- THE MAGAZINE
A BI-200SM goniometer with a BI-9000AT autocorrelator from Brookhaven Instruments recently helped researchers at the Brookhaven National Laboratory (no connection between the two organizations) to solve the enigma of why aqueous molybdenum solutions are blue. "Molybdenum and oxygen can combine to form a wide variety of structures, and some polyoxomolybdate (POM) molecules are the biggest inorganic molecules known, achieving similar sizes to proteins," said Dr. Tianbo Liu in the laboratory's department of physics. "The electronic state of the POMs is responsible for imparting a blue color to the surrounding solution, as the giant POMs cluster together rather than existing as single ions. Because of the size of the POMs, we realized we could use light scattering to find out the actual structure of the complexes and we subsequently discovered a unique blackberry arrangement that we believe represents a new, stable solute state. It has changed our understanding of the solution behavior of inorganic molecules when they reach nanometer sizes."