Gluteraldehyde is a liquid agent used commonly as a cell fixative for electron microscopy. A 2% solution can effectively kill vegetative bacterial cells, fungi and inactivate viruses after 10 minutes.
Formaldehyde is a gas, normally dissolved at 37% concentration in water. It is used as a tissue preservative by morticians and can be used to disinfect surgical instruments and rooms. This compound is carcinogenic, however, so must be handled with extreme care.