TY - JOUR
T1 - Uncovering new transition metal Zintl phases by cation substitution
T2 - the crystal chemistry of Ca3CuGe3and Ca2+nMnxAg2−x+zGe2+n−z(n= 3, 4)
AU - Ponou, Siméon
AU - Miller, Gordon J.
AU - Mudring, Anja V.
N1 - Publisher Copyright:
© The Royal Society of Chemistry 2021.
PY - 2021/4/14
Y1 - 2021/4/14
N2 - High-temperature solid-state reactions of the respective elements afforded the new transition metal Zintl phases Ca3CuGe3(Sc3NiSi3type, monoclinicC2/m-i7, Pearson codemC28), Ca6MnxAg2−x+zGe6−z(own type, monoclinicP21/m-e14, Pearson codemP28) and, Ca5MnxAg2−x+zGe5−z(Ca5MgAgGe5type, orthorhombicPnma-c12, Pearson codeoP48) as evidenced by single-crystal X-ray diffraction. They are additional representatives of the recently discovered homologous series Ca2+nM2+zGe2+n−z, already reported with M = Ag, Mg. These new phases were rationally prepared, after speculation that Cu and Mn could replace the isovalent Ag and Mg, respectively, to yield isostructural phases. Their crystal chemistry is discussed using established ‘structure directing rules’. Their structures are best described according to the Zintl-Klemm formalism as (Ca2+)(2+n)[M2+zGe2+n−z)]2(2+n)−featuring (poly-)germanide oligomers, [Gen](2n+2)−withn= 1-5. These Zintl anions interact with the highly polarizing small M (Cu, Ag, Mn) cations through their terminal Ge atoms, while the central Ge atoms are in trigonal prismatic coordination with the active metal Ca.Electronic structure calculations using density functional theory (DFT) were conducted on the idealized fully ordered model of “Ca3MGe3” (Sc3NiSi3type) with M = Cu, Ag for an analysis of the chemical bonding and structure stabilizing factors. Our findings suggest that new transition metal Zintl phases can be obtained through partial to complete replacement of the highly polarizing small s-block cations (Li, Mg) in the Ca-(Li,Mg)-(Ge,Si) system by their isovalent transition metals like Ag, Cu, and Mn. However, due to differences in coordination requirements and possible strong metal-metal bonding between the d-block elements, the resulting transition metal phases may not be isostructural with their Li and Mg counterparts, even when featuring the same type of Zintl anions.
AB - High-temperature solid-state reactions of the respective elements afforded the new transition metal Zintl phases Ca3CuGe3(Sc3NiSi3type, monoclinicC2/m-i7, Pearson codemC28), Ca6MnxAg2−x+zGe6−z(own type, monoclinicP21/m-e14, Pearson codemP28) and, Ca5MnxAg2−x+zGe5−z(Ca5MgAgGe5type, orthorhombicPnma-c12, Pearson codeoP48) as evidenced by single-crystal X-ray diffraction. They are additional representatives of the recently discovered homologous series Ca2+nM2+zGe2+n−z, already reported with M = Ag, Mg. These new phases were rationally prepared, after speculation that Cu and Mn could replace the isovalent Ag and Mg, respectively, to yield isostructural phases. Their crystal chemistry is discussed using established ‘structure directing rules’. Their structures are best described according to the Zintl-Klemm formalism as (Ca2+)(2+n)[M2+zGe2+n−z)]2(2+n)−featuring (poly-)germanide oligomers, [Gen](2n+2)−withn= 1-5. These Zintl anions interact with the highly polarizing small M (Cu, Ag, Mn) cations through their terminal Ge atoms, while the central Ge atoms are in trigonal prismatic coordination with the active metal Ca.Electronic structure calculations using density functional theory (DFT) were conducted on the idealized fully ordered model of “Ca3MGe3” (Sc3NiSi3type) with M = Cu, Ag for an analysis of the chemical bonding and structure stabilizing factors. Our findings suggest that new transition metal Zintl phases can be obtained through partial to complete replacement of the highly polarizing small s-block cations (Li, Mg) in the Ca-(Li,Mg)-(Ge,Si) system by their isovalent transition metals like Ag, Cu, and Mn. However, due to differences in coordination requirements and possible strong metal-metal bonding between the d-block elements, the resulting transition metal phases may not be isostructural with their Li and Mg counterparts, even when featuring the same type of Zintl anions.
UR - http://www.scopus.com/inward/record.url?scp=85104095994&partnerID=8YFLogxK
U2 - 10.1039/d1ce00094b
DO - 10.1039/d1ce00094b
M3 - Journal article
AN - SCOPUS:85104095994
SN - 1466-8033
VL - 23
SP - 2711
EP - 2722
JO - CrystEngComm
JF - CrystEngComm
IS - 14
ER -