Thermal conversions of chitosanium dodecahydro-closo-dodecaborate

The thermal behavior of chitosanium dodecahydro-closo-dodecaborate, (C₆O₄H₉NH₃)₂B₁₂H₁₂, was studied by thermal analysis, X-ray diffraction, and IR and X-ray photoelectron spectroscopy. As this compound is heated at a rate above 10-20 K/min, it ignites at a temperature of about 300°C. As the compound is heated to 1000°C at a rate below 10 K/min in an inert atmosphere, it yields a mixture of carbon and amorphous boron and/or boron carbides. The presence of a small amount of boron oxide in the product is explained by the formation of a partially oxidized hydroborate anion at the early stages of (C₆O₄H₉NH₃)₂B₁₂H₁₂ decomposition via the interaction between oxygen of the chitosanium cation and the B₁₂H ₁₂ ²⁻ anion. Heating the initial compound in air at a rate below 10 K/min yields carbon and boron oxide as the main products. Molten boron oxide protects boron and/or boron carbides and boron nitride forming in small amounts in the particle bulk from oxidation.