Synthesis and crystal structure of Ba26B12Si5N27 containing [Si2] dumbbells

Hashimoto, Takayuki; Yamane, Hisanori; Becker, Nils B.; Dronskowski, Richard

doi:10.1016/j.jssc.2015.07.022

Cited by 7 publications

(5 citation statements)

References 54 publications

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“…According to this prediction based on the Zintl-Klemm idea, one would expect that silicon dumbbells are present in crystal structure of the ternary LiY 2 Si 2 that should show characteristics of a metal. Indeed, an examination of the crystal structure (Figure 2) reveals the presence of short SiÀ Si distances, which scale in the range typically observed for silicon dumbbells; however, the SiÀ Si separations in the dumbbells are slightly smaller than the distances previously determined [33] for silicon dumbbells (2.44 Å-2.49 Å) carrying a formal charge of À 6. On the other hand, the aforementioned prediction is also in good agreement with the Fermi level characteristics, because the Fermi level in LiY 2 Si 2 falls at a maximum of the DOS so that an electronically unfavorable situation [34] could be present for this compound; yet, which feature in the crystal structure could be related to the extra electron proposed by the Zintl-Klemm approach?…”

Section: Resultsmentioning

confidence: 73%

“…While the results of the charge population analysis clearly indicate that the silicon atoms are reduced, the homoatomic SiÀ Si interactions change from bonding to antibonding states below the Fermi level (Figure 2b) -a circumstance that has also been previously [33,35] encountered in the examination of the electronic structures of silicon dumbbells. An integration of the SiÀ Si -pCOHP and COBI (À IpCOHP and ICOBI) clearly points to a net bonding character for these homoatomic interactions; yet, the ICOBI values corresponding to the silicon dumbbells are slightly smaller than those of the CÀ C bonds in diamond [25] (ICOBI diamond = 0.95).…”

Section: Resultsmentioning

confidence: 86%

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Revisiting the frontier of the Zintl–Klemm approach for the examples of three Mo₂FeB₂‐type intermetallics by means of quantumchemical techniques

Steinberg

2023

Zeitschrift anorg allge chemie

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The Zintl−Klemm idea is a remarkable formalism that can guide us through the crystal structure−electronic structure relationships of solids showing a particular correlation between charge transfers, (8−N) rule and the corresponding structural fragments. Accordingly, this approach has been applied to interpret the relationships between the crystal and electronic structures for numerous intermetallics; yet, are all of these applications of the Zintl−Klemm idea indeed helpful? To answer this question, quantumchemical means were used to explore the electronic structures of three prototypical intermetallics, i.e. LiY2Si2, Sc2Si2Al, and Y2Pd2In. These compounds crystallize with the Mo2FeB2 type of structure whose structure model may be derived from that of the widely encountered U3Si2‐type. The explorations of the electronic structures included examinations of the Mulliken charges, the projected crystal orbital Hamilton populations (pCOHP), the recently introduced crystal orbital bond indices (COBI) and the respective integrated pCOHP as well as COBI values (IpCOHP and ICOBI). The outcome of these investigations indicates that widely diverse types of bonding are evident for the inspected intermetallics so that the predictive power of the Zintl−Klemm idea is limited.

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Section: Resultsmentioning

confidence: 73%

Section: Resultsmentioning

confidence: 86%

Revisiting the frontier of the Zintl–Klemm approach for the examples of three Mo₂FeB₂‐type intermetallics by means of quantumchemical techniques

Steinberg

2023

Zeitschrift anorg allge chemie

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“…For silicides, stannides, and plumbides as well as pnicogenides, the situation is similar; quite a few compounds containing dumbbells are known but their electron counts never suggest a true double bond, and the bond lengths are at least in the range of the elemental single bond …”

Section: Methodsmentioning

confidence: 99%

[Ge₂]⁴⁻ Dumbbells with Very Short Ge−Ge Distances in the Zintl Phase Li₃NaGe₂: A Solid‐State Equivalent to Molecular O₂

et al. 2015

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4À unit is characterized by the shortest GeÀGe distance (2.390(1) ) ever observed in aZintl phase and thus represents the first Ge = Ge double bond under such conditions,a sa lso suggested by the (8ÀN) rule.R aman measurements support these findings.T he multiple-bond character is confirmed by electronic-structure calculations,and an upfield 6 Li NMR shift of À10.0 ppm, whichwas assigned to the Li cations surrounded by the p systems of three Ge dumbbells,further underlines this interpretation. Fort he unperturbed, ligand-free dumbbell in Li 3 NaGe 2 ,the p-bonding p y and p z orbitals are degenerate as in molecular oxygen, which has singly occupied orbitals.T he partially filled p-type bands of the neat solid Li 3 NaGe 2 cross the Fermi level, resulting in metallic properties.Li 3 NaGe 2 was synthesized from the elements as well as from binary reactants and subsequently characterized crystallographically.Multiple bonds of the heavier homologues of boron, carbon, and nitrogen have been intensively investigated during the last decades.[1-3] Among those,t he heavier tetrel homologues all adopt a trans-bent structure in contrast to planar ethylene.The pyramidalization at the Eatom in R 2 E= ER 2 drastically influences the possibility of forming aclassical p bond between the two metal atoms for E = Ge,Sn, and Pb.TheC GMT model proposed by Tr inquier and Malrieu [4] traces the deviation from planarity in R 2 E=ER 2 molecules back to the relative values of the singlet and triplet energies of the monomeric units ER 2 (E S and E T ,r espectively) and the energy of the double-bonded system:F or E s+ +p > 2 DE SÀT ac lassical planar structure is obtained, whereas E s+ +p < 2 DE SÀT favors the trans-bent structure.E s+ +p < DE SÀT results in monomeric ER 2 fragments without E À Eb onding. [1,5] Theinteratomic EÀEdistance is another strong indicator for the bond order.S cheme 1g ives an overview of several homonuclear double-bonded Si and Ge species.F or secondrow elements,double bonds are considerably shorter than the sum of the covalent radii, whereas for the heavier homologues,d eviations occur owing to the strict requirements of the bulky ligands that are often used to stabilize the reactive bonds or owing to electrostatic repulsion in the case of charged systems.F or example,i nR 2 Ge = GeR 2 ,t he Ge À Ge bond lengths are in the range of 2.21 to 2.51 , [2] most of them being shorter than aG e ÀGe single bond (2.44 ), but for [RGe=GeR] 2À ,greater bond lengths are observed.[6]In general, trans-bent structures are energetically favored over planar structures.L igand-free and thus symmetrically unperturbed germanide dumbbells have been observed in Zintl phases. [7] Assuming acomplete valence electron transfer in BaMg 2 Ge 2 ,a14 valence electron [GeÀGe] 6À dumbbell should be obtained. However,t he GeÀGe bond (2.58 ) [8] is significantly longer than atypical Ge single bond, which was sketchily explained by Coulombic repulsion of the negatively charged atoms.R ecently,t he strong interaction of alkalineearth metal dstat...

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“…give convincing evidence that the Zintl compound Li 3 NaGe 2 contains Ge 2 4− dumbbells with a Ge−Ge double bond. To date, there is no clear evidence for a solid with an analogous [Si=Si] 4− dumbbell . Most importantly, the Ge 2 dumbbell in Li 3 NaGe 2 is not bound to any substituents, which leads to several interesting consequences.…”

Section: Figurementioning

confidence: 99%

[Ge=Ge]⁴⁻ Dumbbells in the Zintl Phase Li₃NaGe₂

Ruschewitz

2016

Angew Chem Int Ed

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Synthesis and crystal structure of Ba26B12Si5N27 containing [Si2] dumbbells

Cited by 7 publications

References 54 publications

Revisiting the frontier of the Zintl–Klemm approach for the examples of three Mo₂FeB₂‐type intermetallics by means of quantumchemical techniques

Revisiting the frontier of the Zintl–Klemm approach for the examples of three Mo₂FeB₂‐type intermetallics by means of quantumchemical techniques

[Ge₂]⁴⁻ Dumbbells with Very Short Ge−Ge Distances in the Zintl Phase Li₃NaGe₂: A Solid‐State Equivalent to Molecular O₂

[Ge=Ge]⁴⁻ Dumbbells in the Zintl Phase Li₃NaGe₂

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Synthesis and crystal structure of Ba26B12Si5N27 containing [Si2] dumbbells

Cited by 7 publications

References 54 publications

Revisiting the frontier of the Zintl–Klemm approach for the examples of three Mo2FeB2‐type intermetallics by means of quantumchemical techniques

Revisiting the frontier of the Zintl–Klemm approach for the examples of three Mo2FeB2‐type intermetallics by means of quantumchemical techniques

[Ge2]4− Dumbbells with Very Short Ge−Ge Distances in the Zintl Phase Li3NaGe2: A Solid‐State Equivalent to Molecular O2

[Ge=Ge]4− Dumbbells in the Zintl Phase Li3NaGe2

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Revisiting the frontier of the Zintl–Klemm approach for the examples of three Mo₂FeB₂‐type intermetallics by means of quantumchemical techniques

Revisiting the frontier of the Zintl–Klemm approach for the examples of three Mo₂FeB₂‐type intermetallics by means of quantumchemical techniques

[Ge₂]⁴⁻ Dumbbells with Very Short Ge−Ge Distances in the Zintl Phase Li₃NaGe₂: A Solid‐State Equivalent to Molecular O₂

[Ge=Ge]⁴⁻ Dumbbells in the Zintl Phase Li₃NaGe₂