Nitrile oxides have the chemical formula . Their general structure is . The R stands for any group (typically organyl, e.g., acetonitrile oxide , hydrogen in the case of fulminic acid , or halogen, e.g., chlorine fulminate ). They and are used in 1,3-dipolar cycloadditions. They undergo type 1 dyotropic rearrangement to isocyanates. Nitrile oxides can be synthesised by dehydrogenation of oximes or by dehydration of nitroalkanes. They can be used to synthesise isoxazoles.