Controlling superstructural ordering in the clathrate-I Ba₈M₁₆P₃₀(M = Cu, Zn) through the formation of metal–metal bonds

Abstract

Formation and avoidance of M–M bonds in the clathrate framework result in extreme structural complexity.

High-efficiency thermoelectric Ba8Cu14Ge6P26: bridging the gap between tetrel-based and tetrel-free clathrates

“…The clathrate Ba 8 Cu 16 P 30 was reported to exhibit metallic properties due to an insufficient number of valence electrons to form four bonds per clathrate framework atom. 25 , 33 , 34 In this work we realized an electron-balanced compound by the replacement of some Cu (1 valence electron) and P (5 valence electrons) atoms with Ge (4 valence electrons) atoms. Several synthesized samples with different nominal Ba/Ge/Cu/P ratios contained the same phase with a similar composition as was evidenced by EDX and unit cell parameter determinations.…”

The Smaller the Better: Hosting Trivalent Rare-Earth Guests in Cu–P Clathrate Cages

“…10 frameworks, which are versatile with respect to their chemical bonding, cage sizes, and topology. [23][24][25][26] The smallest among all clathrate cages has been realized in Ba 8 Cu 16 P 30 , where pentagonal dodecahedra with volumes of 97.4 Å 3 and 101.5 Å 3 are present ( Figure 2). Those cages are smaller than the cages in Si-based clathrates: Na 8 30 Our computations predict that the fully relaxed hypothetical compound Ba 6 La 2 Cu 16 P 30 will exhibit 5% less volume of pentagonal dodecahedra than Ba 8 Cu 16 P 30 (Figure 2).…”

“…10,32,33 has the capacity to accept two electrons per formula unit. 24,25 Thus, Ba 8 Cu 16 P 30 is a suitable platform for the incorporation of trivalent rare-earth metals.…”

Phonon glass behavior beyond traditional cage structures: synthesis, crystal and electronic structure, and properties of KMg4Sb3

“…[23][24][25][26][27][28][29] Magnesium and antimony are such elements which have been widely used in thermoelectric field, [26,[30][31][32][33] including the binary Mg3Sb2 phase. [34][35][36][37] In analogy to pnictide-based clathrates, [38][39][40][41] we considered Mg and Sb as promising framework-building elements capable to encapsulate rattling cations. Indeed, clathrates with Zn-Sb and Cd-Sb frameworks and Rb or Cs cationic guests have been reported.…”