I want to know the answer to the following question:
Along with uranyl formate, what product of uranium is used in transmission electron microscopy?
All the background I'm provided with is that "Uranyl acetate and uranyl formate are used as electron-dense "stains" in transmission electron microscopy, to increase the contrast of biological specimens in ultrathin sections and in negative staining of viruses, isolated cell organelles and macromolecules.". Is that enough to answer the question?