“…In each anion, two .Cu--X bonds are involved in bridges to adjacent 2+ --C4H~4N2 .CuB~ , C4H~4N2+.CuCI~ -, CsHI6N2+.CUB~ -AND CsH~6N 2+:CuCI~-anions while the other two Cu--X bonds are nearly normal to the layer. The alkyldiammonium (ADA) series, (H3NCnH2nNH3)CuX4, form structures with eclipsed adjacent layers (Anderson & Willett, 1971;Birrel & Zaslow, 1972;Phelps, Losee, Hatfield & Hodgson, 1976;Tichy, Benes, Haelg & Arend, 1978;Halvorson & Willett, 1988). These eclipsed structures have bonds on adjacent layers nearly directly over each other and show much stronger interlayer magnetic interactions, presumably via superexchange through a two-halide bridge (Phelps, Losee, Hatfield & Hodgson, 1976;Von Kanel, 1979;Snively, Seifurt, Emerson & Drumheller, 1979;Snively, Drumheller & Emerson, 1981;Snively, Tuthill & Drumheller, 1981;Snively, Haines, Emerson & Drumheller, 1982;Rubenacker, Haines, Drumheller & Emerson, 1984;Halvorson & Willett, 1988;Middleton, Place & Willett, 1988).…”