Symbol (chemistry) the material was known in ancient times, while for others, the name is a more recent invention. For example, "He" is the symbol for helium (New Latin name, not known in ancient Roman times), "Pb" for lead ("plumbum" in Latin), and "Hg" for mercury ("hydrargyrum" in Greek). Some symbols come from other sources, like "W" for tungsten ("Wolfram" in German, not known in Roman times). Temporary symbols assigned to newly or not-yet synthesized elements use 3-letter symbols based on their atomic numbers. For example, "Uno" was the temporary symbol for hassium (element 108) which had the temporary name of "unniloctium".
Period 5 element other silver compounds are used as disinfectants and microbiocides. While many medical antimicrobial uses of silver have been supplanted by antibiotics, further research into clinical potential continues. Cadmium is a chemical element with the symbol Cd and atomic number 48. This soft, bluish-white metal is chemically similar to the two other stable metals in group 12, zinc and mercury. Like zinc, it prefers oxidation state +2 in most of its compounds and like mercury it shows a low melting point compared to transition metals. Cadmium and its congeners are not always considered transition metals, in that they do not have