Period 6 element between barium and hafnium, and radium and rutherfordium, respectively. This convention is entirely a matter of aesthetics and formatting practicality; a rarely used wide-formatted periodic table inserts the lanthanide and actinide series in their proper places, as parts of the table's sixth and seventh rows (periods). Lanthanum is a chemical element with the symbol La and atomic number 57. It is the first element in the lanthanide series. It is a soft, ductile, silvery-white metal that tarnishes rapidly when exposed to air and is soft enough to be cut with a knife. It is the eponym of the lanthanide series,
Silver nitride Silver nitride Silver nitride is an explosive chemical compound with symbol AgN. It is a black, metallic-looking solid which is formed when silver oxide or silver nitrate is dissolved in concentrated solutions of ammonia, causing formation of the diammine silver complex which subsequently breaks down to AgN. The standard free energy of the compound is about +315 kJ/mol, making it an endothermic compound which decomposes explosively to metallic silver and nitrogen gas. Silver nitride was formerly referred to as fulminating silver, but this can cause confusion with silver fulminate or silver azide, other compounds which have also been referred to