“…Recently, M 1− x Ni x (H 2 PO 4 ) 2 · x H 2 O (M = Mg, Mn, Fe, Co, Zn, and Cd) were prepared by corresponding metal carbonates and phosphoric acid at 293 K for 2−90 days . More recently, Mn 1− x A x (H 2 PO 4 ) 2 · x H 2 O (A = Ca, Fe, Co, Ni, and Cu) were prepared by metal sources (Mn (c; complexometric) or MnCO 3 and A(II) = CaCO 3 , Fe, CoCO 3 , NiCO 3 , or CuCO 3 ) and phosphoric acid H 3 PO 4 at ambient temperature for 20 s. These procedures were strong exothermic reactions and evolved gases (CO 2 and H 2 ). − However, a limited dose of M 1− x A x (H 2 PO 4 ) 2 · n H 2 O could be synthesized without toxic gases.…”