Abstract
An ambient-pressuresolutionrouteandanimprovedsolvothermalsyntheticmethodhavebeende-
veloped toproducepolycrystallinepowdersandlargesinglecrystalsofNH4MCl2(HCOO) (M¼Fe, Co,Ni).
The magneticstructureofthe1DlinearchaincompoundNH4FeCl2(HCOO) hasbeendeterminedbylow-
temperatureneutronpowderdiffraction,revealingferromagneticintra-chaininteractionsandanti-
ferromagnetic inter-chaininteractions.Thenewly-reportedCoandNianalogsareisostructuralwith
NH4FeCl2(HCOO), buttherearesignificant differencesinthemagneticpropertiesofeachcompound;the
Ni analogbehavessimilarlytotheFecompoundbutwithstrongermagneticcoupling,exhibitinganti-
ferromagnetic ordering(TN=8.5 K)andabroadmetamagnetictransitionbetween2and5T,whiletheCo
analog doesnotordermagneticallyabove2K,despitestrongantiferromagneticnearest-neighborin-
teractions.
