Magnetically Frustrated Quaternary Chalcogenides with Interpenetrating Diamond Lattices

Abstract

A series of quaternary sulfides of the composition NaMGaS (M = Mn (1), Fe (2), and Co (3)) have been synthesized in sealed quartz ampules. In these compounds, divalent transition metal and Ga occupy the same crystallographic site in the Ga-S network, forming a supertetrahedral, T2 (adamantane) unit, through the corner-sharing of four M/GaS tetrahedra. The corner sulfur atoms of the T2 clusters are further connected to similar T2 units to form an open continuous three-dimensional (3D) anionic framework of composition {[GaMS]}. The framework resembles a zinc blende structure type if each T2 cluster is considered as a single tetrahedron and two such frameworks are intertwined to generate channels wherein reside the extra-framework Na ions. Placement of transition metals (Mn or Fe or Co) in the corner of a perfect supertetrahedron, adamantane building unit, generates an ideal lattice for geometrical magnetic frustration, which, on dilution with nonmagnetic metal (Ga), creates an ideal case for random frustration. Preliminary magnetic measurements indicate high negative values of the Weiss constant (-200 to -400 K) and the absence of any magnetic ordering, reinforcing the presence of magnetic frustration in all of these compounds.

Phase Matchability Transformation in the Infrared Nonlinear Optical Materials with Diamond‐Like Frameworks

“…The asymmetric unit consists of two crystallographically unique Cs atoms, six Mn atoms, ten Ga atoms and twenty‐two S atoms. All Mn and Ga atoms are linked to S atoms tetra‐coordinatedly with MnS and GaS distances in the normal range of 2.351(6)–2.441(6) Å and 2.238(5)–2.363(7) Å, respectively (Table S4, Supporting Information), consistent with those in Na 3 MnGaS 4 [ 28 ] (Mn/GaS: 2.31–2.37 Å) and AgCd 0.85 Mn 1.15 GaS 4 [ 29 ] (MnS: 2.44–2.50 Å; GaS: 2.24–2.33 Å). In this complicated structure, six unique [MnS 4 ] tetrahedra first make up three kinds of MnS ABBs, namely [MnS 4 ] , [Mn 2 S 7 ] and [Mn 3 S 9 ] groups ( Figure a,b).…”

High Sodium-Ion Conductivity in Interlocked Quaternary Chalcogenides Built with Supertetrahedral Building Units

“…However, in the absence of any remaining unaccounted-for e-density, the weighted R factor wR 2 did not converge to a low value though the isotropic thermal parameters were reasonably good. A similar situation was encountered while solving isostructural compounds involving transition metals (Na 3 M GaS 4 , M = Mn, Fe, and Co), for which a Ga/ M mixed occupancy was found . By a similar analogy, Ga and Zn occupancies were refined freely, yielding 50% occupancy for both Ga and Zn, and the weighted R factor ( wR 2 ) reduced significantly.…”

“…Selected bond lengths for the compounds are given in Table . The detailed structural description can be found in our previous publication, and here, we will only briefly describe the salient features . Ga/Zn– Q tetrahedral units form a supertetrahedral (T2) building units through corner sharing (Figure b–d).…”

“…Taking advantage of the HSAB theory, relatively softer ions compared to P +5 and Sb +5 , for example, Ga 3+ and Zn 2+ , can be chosen to build a moisture stable framework by connecting GaS 4 and ZnS 4 polyhedra. This hypothesis lead us to consider our recently reported Na 3 M GaS 4 (M = Mn, Fe, and Co) structure type built with supertetrahedral T2 (adamantane type) units, which has a large tunnel filled with Na ions . Our investigation in the Ga-chalcogenide system also resulted in several new ternary thiogallates in both Li and Na systems. , Therefore, we extended the Na 3 M GaS 4 structure type to Zn and into selenide analogues to create moisture stable quaternary compounds, Na 3 M GaQ 4 ( Q = S/Se, M = Zn).…”

Dielectric and Magnetic Relaxations Exhibited in a 2D Parallel Interpenetrating Frustrated Star Net

“…Particularly, two adjacent “star” nets interpenetrate to form a rare 2D parallel interpenetrating network (Figure 2c and 2d), which grows along the (0, 1, 0) plane. Though some 2D frustrated nets have been already reported, the interpenetrating frustrated network in 1 is very rare [15,21] . The [HDMPDA] + cations with two‐fold fill in the free space of the interpenetrating net.…”