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The synthesis and the chemical, structural, magnetic, and Mössbauer spectral characterization of three synthetic alluaudites, Na₂Mn₂Fe(PO₄)₃, NaMn Fe₂(PO₄)₃ and Na₂MnFe^IIFe^III(PO₄)₃, and a natural sample with the nominal composition of NaMn Fe₂(PO₄)₃, collected in the Buranga pegmatite, Rwanda, are reported. All four compounds have the expected alluaudite monoclinic C2/c structure with the general formula [A(2)A(2)’][A(1)A(1)’A(1)₂”]M(1)M(2)₂(PO₄)₃ in which manganese(II) is on the M(1) site and manganese(II), iron(III) and, in some cases, iron(II) on the M(2) site. The X-ray structure of Na₂Mn₂Fe(PO₄)₃ also indicates a partially disordered distribution of Na^I and Mn^II on the M(1) and A(1) crystallographic sites. All four compounds are paramagnetic above 40 K and antiferromagnetically ordered below. Above 40 K the effective magnetic moments of NaMnFe₂(PO₄)₃ and Na₂MnFe^IIFe^III(PO₄ …