Convert from electron to libra [Portugal, Spain]

Unit Definition (electron)
The electron is the mass of the electron, often used as a unit of mass in particle physics. An electron has a mass of about 9.109 382 x 10E-31 kilogram, 9.109 382 x 10E-28 gram, or 0.510 9989 million electronvolts.

Unit Definition (libra [Portugal, Spain])
The libra [Portugal, Spain] a traditional unit of weight. The libra was the Roman unit from which the English pound is descended; the symbol "lb" for the pound comes from this unit. The Spanish and Portuguese units are larger, generally in the range from 1.011 to 1.016 English pound (very close to 460 grams). The Spanish libra equals 16 onzas, and the Portuguese libra equals 16 onças. The word "libra" is sometimes used now for the kilogram, a much larger unit.