A convenient pathway to new molecular organo-lanthanide-polyarsenides in general and to a f-element complex with the largest polyarsenide ligand in detail is reported. For this purpose, the activation of the solid state material As0 nano (nanoscale gray arsenic) by the multi electron reducing agents [K(18-crown-6)][(Ln+II)2(μ-η6:η6-C6H6)] (Ln = La, Ce, Cp'' = 1,3-bis(trimethylsilyl)cyclopentadienyl anion) and [K(18-crown-6)]2[(Ln+II)2(μ-η6:η6-C6H6)] (Ln = Ce, Nd) is shown. These non-classical divalent lanthanide compounds were used as three and four electron reducing agents where the product formation can be directed by variation of the applied reactant. The obtained Zintl anions As3 3-, As7 3-, and As14 4- were previously not accessible in molecular 4f-element chemistry. Additionally, the corresponding compounds with As14 4--moieties represent the largest organo-lanthanide-polyarsenides known to date.
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