Facile Syntheses and Structures of New Metal-maleonitrilediselenolates: [K([2.2.2]-cryptand)]3[Ag{Se2C2(CN)x}(Se6)], [K([2.2.2]-cryptand)]2 [Ni{Se2C2(CN)2}2], and Ni(dppp){Se2C2(CN)2}. Article