W was the 19th letter and was pronounced "wah"; there was an equivalent letter in the old Baybayin script of the Philippines. In the International Phonetic Alphabet, is used for the voiced labial-velar approximant. W is the symbol for the chemical element tungsten, after its German (and alternative English) name, "Wolfram". It is also the SI symbol for the watt, the standard unit of power. Double-u, whose name reflects stages in the letter's evolution when it was considered two of the same letter, a double U, is the only modern English letter whose name has more than one syllable. It is
Chemical element or an electrophile; similarly "Nu" denotes a nucleophile. "L" is used to represent a general ligand in inorganic and organometallic chemistry. "M" is also often used in place of a general metal. At least two additional, two-letter generic chemical symbols are also in informal usage, "Ln" for any lanthanide element and "An" for any actinide element. "Rg" was formerly used for any rare gas element, but the group of rare gases has now been renamed noble gases and the symbol "Rg" has now been assigned to the element roentgenium. Isotopes are distinguished by the atomic mass number (total protons and