boron sulfide is a yellow solid with a pungent odor. It is a member of the chalcogenide family and combines with metal ions to form borate compounds such as boron trichloride and boron sulfate. In addition, boron sulfide is useful as a catalyst in certain reactions. It is also known as pyroboron sulfide or boron trisulfide.
The chemistry of boron sulfide has attracted significant attention because of its unique properties, particularly its ability to conduct electricity in a wide temperature range. The element is also able to react with hydrogen at high temperatures without decomposition to produce boric acid and gaseous hydrogen sulfide.
Although various methods have been proposed to prepare boron sulfide, the yields obtained are usually low and considerable sintering occurs during the reaction. The present invention provides a process for preparing substantially pure boron trisulfide. The method comprises fluidizing a bed of powdered solid calcium boride with an inert gas, heating the bed to about 900 C., and passing hydrogen sulfide through the fluidized mixture to re react with the amorphous boron in the bed. The boron trisulfide evolved is recovered from the reaction solution.
By using a combination of extreme pressure – high temperature synthesis and ab initio evolutionary crystal structure prediction, two new boron-rich chalcogenides have been discovered. These are boron-rich sulfide B6S and boron-rich selenide B6Se, which both have orthorhombic symmetry and belong to the Pmna space group. Rietveld refinement of synchrotron powder X-ray diffraction data was used to determine the crystal structures of the boron-rich chalcogenides, and the experimentally observed Raman bands were assigned to phonon modes by use of an atomically correlated full-width-half-maximum broadening technique.