Semiconducting silicon–phosphorus frameworks for caging exotic polycations

Abstract

A series of novel semiconductors AAe6Si12P20X (A = Na, K, Rb, Cs; Ae = Sr, Ba; X = Cl, Br, I) is reported. Their crystal structures feature tetrahedral Si-P framework...

BaCuTP2 (T = Al, Ga, In): a semiconducting black sheep in the ThCr2Si2 intermetallic family

“…When paired with SCXRD, ssNMR provides a complimentary technique to verify the SCXRD model and overcome certain SCXRD limitations. [31][32][33][34][35][36] Here, 31 P ssNMR spectroscopy was performed to probe possible local ordering, which is not detected by the long-range probing techniques, such as X-ray diffraction. According to the X-ray crystallography model, P has only one unique site in the I4/mmm crystal structures of BaCuAlP 2 and BaCuGaP 2 , yet the 31 P ssNMR spectra of both compounds show two inhomogeneously broadened asymmetrical peaks with peak maxima at −206 ppm and −258 ppm for BaCuAlP 2 and at −214 ppm and −264 ppm for BaCuGaP 2 (Fig.…”

ABa6Cu31Te22 (A = K, Rb, Cs) Featuring Polyanionic Copper–Telluride Frameworks with Ultralow Thermal Conductivity

“…The A –Te distances are approximately 4.10 Å. For comparison, in unconventional clathrates Cs 8 Zn 18– x Cd x Sb 28 , two types of Cs-containing polyhedral cages were reported, one with a volume of 160–170 Å 3 and the other having a much larger cage volume of 220 Å 3 , despite shorter nearest Cs–Sb distances of 3.79 Å. , For K-containing clathrates, such as for K 58 Zn 122 Sb 207 , various types of polyhedral Zn–Sb cages were reported, with the smallest ones being around ∼155 Å 3 . Rattling of the K or Cs atoms in the large cages was reported to play an important role in lowering thermal conductivity.…”

Machine Learning-Guided Discovery of Ternary Compounds Containing La, P, and Group 14 Elements

“…It should be noted that partial occupancies and atomic mixings between Si and P are not considered in our predictions because it is challenging for DFT to deal with such situations. Nevertheless, majority of studied M–Si–P phases show no such mixing. − Initial assignment of Si/P is done based on single-crystal X-ray diffraction. High quality datasets allow to refine P/Si.…”

“…High quality datasets allow to refine P/Si. We have utilized 31 P and 29 Si solid-state NMR spectroscopy to verify Si/P assignments. − We hypothesized that the ML-guided DFT predictions for ordered La–Si–P system are reliable.…”