Synthesis and Crystal Structure of M11X10 Compounds, M=Sr, Ba and X=Bi, Sb. Electronic Requirements and Chemical Bonding

Synthesis and crystal structure of a new Zintl phase Sr5In2Bi6

“…The Bi-Bi distance of 3.159(2)Å corresponds to a Pauling single bond. It is slightly shorter than that of the Bi 2 4− dumbbell (3.27Å) in Sr 11 Bi 10 [24], as well as that of the zigzag Bi chains of EuBi 2 (3.225Å) [25].…”

High-temperature thermoelectric studies of A11Sb10 (A=Yb, Ca)

“…The X 4 4À anion shows a large separation between the HOMO and LUMO confirming the stability of the square planar anion. The crystal orbital overlap populations (COOP) for different diatomic interactions show antibonding character near the Fermi level and with the cation-anion (M-X) bands consistent with bonding interaction [14]. Competing effects of n-and p-type carriers lead to low values for both Hall mobility and thermopower (absolute value of Seebeck) and a deviation of the typical temperature dependence expected from a single band, single carrier reaching maximum values of +23 and +20 mV/K at 1000 and 1100 K, respectively, indicating p-type behavior for both materials.…”

“…Theoretical calculations using molecular orbital and periodic tight binding method have been published for M 11 X 10 (M ¼ Sr, Ba; X ¼ Sb, Bi) [14]. The anions can be considered isolated and for X 2 4À , the HOMO is degenerate (p g ) and corresponds to the p y p z nonbonding orbitals.…”

“…Two binary Zintl compounds, A 11 Sb 10 (A ¼ Yb, Ca) have been synthesized and possess promising thermoelectric traits [9], that could potentially lead to the discovery of improved thermoelectric device efficiencies [10][11][12][13][14]. Yb 11 Sb 10 is isostructural to Ho 11 Ge 10 , crystallizing in the body-centered, tetragonal unit cell, space group I4/ mmm, with Z ¼ 4 [13].…”

Experimental and theoretical investigations for site preference and anisotropic size change of RE11Ge4In6−xMx (RE=La, Ce; M=Li, Ge; x=1, 1.96)

“…In particular, the series of ternary indide compounds including the RE 11 Ge 8 In 2 (RE = Gd-Tm) system [19] and the RE 11 Tt 4 In 6 (RE = Y, La, Gd-Er; Tt = Si, Ge) system [20,21] has been known for its interesting magnetocaloric effect. Moreover, a series of isotypic binary or ternary pnictides with some triel or tetrel substitutions including the A 11 Pn 10-x T x (A = Rb, Cs, Ca, Sr, Ba, Eu, Yb; Pn = Sb, Bi; and T = Si, Ge, Sn) system [18,[22][23][24] has been thoroughly studied given its particular thermoelectric property. However, despite the large amounts of researches on these systems, the majority of studies have been focused on the crystal structures and the physical properties.…”