New sodium-rich mixed Mn/In chalcogenido metallates Na ₁₂ MnIn ₂ Q ₁₀ (Q = S, Se)

Abstract

The sodium-rich sulfido and selenido metallates Na12MnIn2Q10 (Q = S/Se) were synthesized in pure phase from melts composed of stoichiometric quantities of the manganese monochalcogenides MnQ, elemental indium and the chalcogens together with either Na2S (Q = S) or elemental sodium (Q = Se) as starting material. The samples were heated up to maximum temperatures of 1000/900 °C under an argon atmosphere; crystallization was achieved by slow cooling rates of 10 K h−1. The two isotypic compounds (monoclinic, space group P21/m, a = 678.26(2)/698.85(10), b = 2202.77(7)/2298.7(3), c = 766.39(3)/800.59(13) pm, β = 90.232(2)/90.147(5)°, Z = 2, R1 = 0.0516/0.0575) crystallize in a new structure type. According to the division of the formula as Na12[InQ4][MnInQ6] the salts contain ortho indate anions [InIIIQ4]5− besides hetero-bimetallic dimers [MnIIInIIIQ6]7−, which consist of two edge-sharing [MQ4] tetrahedra. The seven crystallographically different sodium cations exhibit an either tetrahedral or octahedral coordination by the chalcogen atoms. Thus, the overall structure of the salt is best described by a hexagonal close packing of the sulfide/selenide anions, in which the octahedral voids of every second interlayer section are fully occupied by the (overall 5/f.u.) Na+ positions with CN = 6. In the other half of the interlayer sheets, all tetrahedral voids (overall 10/f.u.) are occupied by the seven CN = 4 Na+ cations, one In3+ of the ortho anion and the two Mn2+/In3+ cations (which statistically occupy one crystallographic site). This structure relation is also verified by a Bärnighausen group-subgroup tree connecting the h.c.p. (Mg type) aristotype (with its tetrahedral and octahedral voids) by an overall index of 60 with the structure of the two title compounds.

K5[InSe4] and K12[InS4]2(S): New Alkali Chalcogenido Indates with [InQ4]5–ortho Anions

“…The two title compounds were obtained initially from Mn‐containing samples with an overall composition K 12 MnIn 2 (S/Se) 10 , which were intended to prepare the K analogs of the new sodium chalcogenides Na 12 [MnIn(S/Se) 6 ][In(S/Se) 4 ] . The latter salts contain the ortho indate anions of the title phases besides the mixed‐valent tetrahedra dimers [MnIn(S/Se) 6 ] 7– , which serve as model systems for the mixed‐valent Fe II /Fe III ferrates like e.g.…”

“…The structure, commonly described by an α-U packing of the whole metallate tetrahedra, exhibits considerably distorted 4-6 CCPs and the ECoN(A) values of the observed structures span a larger range from 3.34 to 5.48 (Table 3). The CN(MQ 4 ) of 14 allows for an "ideal" coordination of the ortho anion coordination number (17)(18)(19). It can be expected, that the yet unexplored rubidium and cesium sulfido, selenido and tellurido salts, which are in the same region of r Q 2-:r A + (1.0-1.4) also exist and show a comparable structure chemistry.…”

“…shown by the successful synthesis of the new compounds with the 3:2:4 (for A:M:Q) composition (i.e. the cluster/chain ferrates family, [17,18] ) as well as by the preparation of compounds containing the heterobimetallic dimers [Mn II In III (S/Se) 6 ] 5-. [19] In the course of this work it became apparent, that even the simple A-rich S/Se/Te indates(III) (and their Al and Ga analogs) as well as the respective manganates(II) are scarcely investigated.…”