Interaction of lanthanum with boron and carbon: phase diagram and structural chemistry

Abstract

8The isothermal section of the La-B-C phase diagram at 1270 K has been investigated by 9 means of X-ray, neutron powder diffraction, microstructure and EPMA analyses. Eight ternary 10 compounds were found, and for six of them the crystal structures have been established. The 11 phase with the structure type of La 5 B 2 C 6 has a broad homogeneity range described by the

A Lanthanum‐Filled Carbon–Boron Clathrate

“…Similar to SrB 3 C 3 , the La counterpart is recoverable to ambient conditions, but must be preserved carefully under an inert atmosphere. When samples are exposed to air/moisture, they degrade into what is presumed to be hydrolysis products (Supporting Information), which is a common feature for other metal borocarbide compounds [14, 21b] . While dynamically stable at atmospheric pressure, we speculate that the 90° C‐B‐C bond angles contribute to the sensitivity of the recovered material.…”

Phase equilibria and crystal structure of compounds of the Tb–B–C system at 1270 K

“…Фаза складу ~Tb2BC3 утворює рівноважні двофазні області зі сполуками TbB2C2, TbC2 та Tb5(B,C)x (8,3 x 9,2), а фаза з найбільшим вмістом Карбону ~Tb4B5C18 -зі сполуками TbC2, TbB2C2, TbB6 та Карбоном. [4,28]. Так, для складу Tb5B2,1C6,2 об'єм елементарної комірки становить 759,35(1) Å 3 , а для Tb5B2,9C5,3 -800,13(2) Å 3 .…”

“…Проведені дослідження кристалічної структури цієї сполуки рентгенівським методом монокристала свідчать про невпорядковане заповнення правильної системи точок 16g атомами Бору та Карбону чотириатомних груп BC3 [12]. У системах La-B-C, Ce-B-C та Pr-B-C [4][5][6] вміст Бору у сполуках цього СТ змінюється у дещо більших межах, ніж для Tb5(BC)x, а в системі Er-B-C він є подібним, що свідчить також про вплив розмірного чинника на область гомогенності. За результатами фазового аналізу сполука складу TbB2C2 утворює фазові рівноваги з чотирма тернарними фазами та двома бінарними (рис.…”

Investigations in the ternary praseodymium–boron–carbon system: Solid-state phase diagram and structural chemistry

“…These finite chains embedded in voids of the metal atom matrix can have different lengths ranging from 2 to 13 non-metal atoms up to now, and chains of different sizes as well as isolated C atoms can coexist [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]. These compounds were revealed from partial or complete investigations of ternary RE-B-C phase diagrams earlier established for most of the rare earth metal elements (RE = Sc, Y, La, Eu, Gd, Ho) [22][23][24][25][26][27]. Novel representatives were recently discovered during our new investigations of the La-B-C [24], Pr-B-C and Nd-B-C systems [20,21].…”

“…These compounds were revealed from partial or complete investigations of ternary RE-B-C phase diagrams earlier established for most of the rare earth metal elements (RE = Sc, Y, La, Eu, Gd, Ho) [22][23][24][25][26][27]. Novel representatives were recently discovered during our new investigations of the La-B-C [24], Pr-B-C and Nd-B-C systems [20,21]. Our latest studies of the isothermal sections of the ternary Pr-B-C phase diagram at 1270 K (concentration range 0-60 at.% Pr) and 1070 K (> 60 at.% Pr), crystallographic data of all the ternary compounds and the structure determinations of the new ternary compound Pr 2 BC and the composition of the solid solution of the phase Pr 5 B 2 C 6 are the subject of this work.…”