Manganese(IV) fluoride hydrofluoric acid. The pentafluoromanganate(1−) salts of potassium, rubidium and caesium, MMnF, can be prepared by fluorination of MMnF or by the reaction of [MnF(py)(HO)] with MF. The lemon-yellow heptafluoromanganate(3−) salts of the same metals, MMnF, have also been prepared. Manganese(IV) fluoride Manganese tetrafluoride, MnF, is the highest fluoride of manganese. It is a powerful oxidizing agent and is used as a means of purifying elemental fluorine. Manganese tetrafluoride was first unequivocally prepared in 1961 by the reaction of manganese(II) fluoride (or other Mn compounds) with a stream of fluorine gas at 550 °C: the MnF sublimes into the gas stream
Hazard symbol carry a significant health risk (biohazards), including viral samples and used hypodermic needles (see sharps waste). The biohazard symbol was developed by the Dow Chemical Company in 1966 for their containment products. According to Charles Baldwin, an environmental-health engineer who contributed to its development: "We wanted something that was memorable but meaningless, so we could educate people as to what it means." In an article in "Science" in 1967, the symbol was presented as the new standard for all biological hazards ("biohazards"). The article explained that over 40 symbols were drawn up by Dow artists, and all of the symbols