Abstract
The compound La24Ru11 (tetra-cosa-lanthanum undeca-ruthenium) crystallizes in a Ce24Co11-type structure. The non-centrosymmetric crystal structure (space group P63 mc) contains RuLa6 trigonal prisms, La6 octa-hedra and LaRu4 tetra-hedra and is closely related to that of Ce23Ni7Mg4. This communication highlights the crystal-chemical similarities and points out the differences between the two structures. All of the tested crystals were inversion twins.
Highlights
The La–Ru system has been extensively studied (Palenzona & Cirafici, 1989)
According to a recent study (Carlsson, 2015), the phase La5Ru3 is believed to be a part of an incommensurate-composite-structure family related to Y44Ru25
During a systematic search for optimal crystal-growth conditions for La5Ru3, the new compound, La24Ru11, was obtained as a secondary product. It crystallizes with a hexagonal unit cell, space group P63mc (186), and with a Ce24Co11 structure type (Larson & Cromer, 1962)
Summary
The La–Ru system has been extensively studied (Palenzona & Cirafici, 1989). The phase diagram contains five binary phases: the Laves phase, LaRu2 (Compton & Matthias, 1959), with the MgCu2-type structure; La5Ru3 (Palenzona & Canepa, 1990a); La7Ru3 (Palenzona & Canepa, 1990b), with the Sr7Pt3-type structure; La5Ru2 (Palenzona, 1979), with the Mn5C2-type structure and La3Ru (Palenzona, 1979), with the cementitetype structure. According to a recent study (Carlsson, 2015), the phase La5Ru3 is believed to be a part of an incommensurate-composite-structure family related to Y44Ru25. During a systematic search for optimal crystal-growth conditions for La5Ru3, the new compound, La24Ru11, was obtained as a secondary product. It crystallizes with a hexagonal unit cell, space group P63mc (186), and with a Ce24Co11 structure type (Larson & Cromer, 1962). According to the Pearson’s Crystal Data (Villars & Cenzual, 2019), the composition ratio of 24:11 is not common and only a few binary compounds having this composition have been reported (Singh & Raman, 1968; Raevskaya et al, 1994). There are several ternary intermetallics with a rare-earth content higher than 60 at.%, including Yb9CuMg4 (De Negri et al, 2016), La43Ni17Mg5 (Solokha et al, 2009a) and Ce23Ni7Mg4 (Solokha et al, 2009b), which share some structural features with the title compound, La24Ru11, described below
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
