Electrum is a metal alloy mainly consisting of gold, silver and traces of some other metals. This naturally occurring alloy has a long history of being used for making coins, vessels and also for coatings. It was referred to as âgoldâ or âwhite goldâ by ancient Greeks.
In Interstitial defect, atom occupies the interstitial space of the lattice structure of solid crystal. In Substitutional defect, the foreign atom occupies only the lattice site of a crystalline solid. Interstitial defect may occur by the atoms of either same solid (called self-interstitial) or foreign material. Substitutional defect is always caused by foreign atoms.
A pars defect of the lumbar spine involves a part of a vertebra called the pars interarticularis. Roughly translated, that means the part between two joints.. A defect in the pars is a break in this portion of bone. This break leads to a separation of the upper, front portion of the vertebra from its lower, back portion.