New members of ternary rare-earth metal boride carbides containing finite boron–carbon chains: RE25B14C26 (RE=Pr, Nd) and Nd25B12C28
Review articleOpen access

AbstractNew ternary rare-earth metal boride carbides RE25B14C26 (RE=Pr, Nd) and Nd25B12C28 were synthesized by co-melting the elements. Nd25B12C28 is stable up to 1440 K. RE25B14C26 (RE=Pr, Nd) exist above 1270 K. The crystal structures were investigated by means of single-crystal X-ray diffraction. Nd25B12C28: space group P1¯, a=8.3209(7) Å, b=8.3231(6) Å, c=29.888(2) Å, α=83.730(9)°, β=83.294(9)°, γ=89.764(9)°. Pr25B14C26: space group P21/c, a=8.4243(5) Å, b=8.4095(6) Å, c=30.828(1) Å, β=105.879(4)°, V=2100.6(2) Å3, (R1=0.048 (wR2=0.088) from 2961 reflections with Io>2σ(Io)); for Nd25B14C26 space group P21/c, Z=2, a=8.3404(6) Å, b=8.3096(6) Å, c=30.599(2) Å, β=106.065(1)°. Their structures consist of a three-dimensional framework of rare-earth metal atoms resulting from the stacking of slightly corrugated and distorted square nets, leading to cavities filled with cumulene-like molecules [B2C4]6− and [B3C3]7−, nearly linear [BC2]5− and bent [BC2]7− units and isolated carbon atoms. Structural and theoretical analysis suggests the ionic formulation for RE25B14C26: (RE3+)25[B2C4]6−([B3C3]7−)2([BC2]5−)4([BC2]7−)2(C4−)4·5e− and for Nd25B12C28: (Nd3+)25([B2C4]6−)3([BC2]5−)4([BC2]7−)2(C4−)4·7e−. Accordingly, extended Hückel tight-binding calculations indicate that the compounds are metallic in character.

Request full text

References (0)

Cited By (0)

No reference data.
No citation data.
Join Copernicus Academic and get access to over 12 million papers authored by 7+ million academics.
Join for free!