The structural family of non-centrosymmetric Zr ₂ Fe ₁₂ P ₇ -type pnictides, tetrelides and halid

Abstract

The Zr ₂ Fe ₁₂ P ₇ -type structure is one of the common structure types of transition metal-rich intermetallic compounds. This structural family is characterized through its broad coloring on the nine crystallographically independent Wyckoff sites. This diverse coloring leads to compounds with distinctly different bonding patterns, i.e., pnictides, tetrelides, halides, and even some hydrides. The Zr ₂ Fe ₁₂ P ₇ -type phases can geometrically be explained through an easy condensation pattern of trigonal prisms, forming shamrock/windmill-like motifs. A central problem is the crystallographic disorder that can occur along the c axis. These structural features are reviewed in the present work, along with the broad magnetic and transport properties.