Ternary borides

Figure 2. Formation of ternary borides and phase equilibria within ternary boride systems of the type M-M-B or M-Y-B (M = metal, Y = honmetal). , complete isothermal section established B, part of a diagram only. Numbers in the lower part of each square correspond to the refs, to the ternary section. The number of ternary compounds observed is indicated in the right upper corner of each square.

Figure 1. Formation of ternary borides MreMj3B2 and different structure types (Mre = rare-earth element, M-p = transition-metal element). , CeCo3B2 type ErIr3B2 type O, URujBj type El, Ndo7,Rh3 29B2 type IS, YOS3B2 type B, Laofi3Rh3B2 type , compound formation observed, but structure type unknown. Refs a , b , c , d e , f g , h , i , j ", k , 1 , m , r, s - , t u = 45 see also ref. 62.

Many ternary borides crystallize with the ordered BaAl4 or ThCr2Si2 structure ... 

Figure 2. Formation of ternary borides MREMT4B4 (Mre = rare-earth element, Mj = transition metal) and different structure types. B, CeCo4B4 type B, LURU4B4 type a, NdCo4B4 type H, YOS4B4 type 8, Sm,4.eFe4B4 type MRcRe4B4 type , LuRh4B4type. Refs b, c , d", e, f , g , h, il l ...

G.7.2.2.2. Ternary Borides with Boron-Boron Chain Formation. 

Ternary Borides wtth Boron-Boron Chein Formation. 

Ternary Borides with Boron-Boron Chain Formation. 

Steinitz, R., and I. Binder New ternary boride compounds. Powder Met. 

Figure 5.35. Schematic indication of the boron atomic arrangements inside the structures of binary and ternary borides as a function of the overall B content (adapted from Rogl 1992).

Borides. New ternary borides TiW4B5 and Ti2W3B5, Hf9Mo3B2 and (Hf,W)i2B2-, " and LnMB (Ln = Y, Tb, Dy, Ho, or Er, M = Mo or have been prepared and their X-ray diffraction patterns determined. 

Superconductivity in the multiphase quaternary borocarbide system Y-Ni-B-C has been recently reported [141,142], Earlier work on valence fluctuations in ternary borides RENiaB were studied and in the case of YNi4B, a weak but reproducible signal of superconductivity at Tc of 12 K was observed. This is the first report or discovery of a ternary superconducting phase of the elements Y, Ni and B with a high Tc value (Fig. 12.27). 

A total of more than 700 ternary borides have been prepared and characterized. Most of these phases occur in the RE-T-B systems. A maximum of 12 ternary phases has, for instance, been found in each of the Sm-Co-B and Ce-Co-B systems (see Figure 1). There are also ternary... 

Owing to the great number of structure types represented among the binary and ternary borides, it is not possible to present in this article even a simple description of all known structure types. The following presentation deals mainly with binary boride structmes. Ternary boride structures show many similarities with those of binary boride phases but cannot be treated in any detail in the present paper because of space limitations. Binary and ternary boride structures are treated in more detail elsewhere. It is convenient to describe here... 

A presentation of binary and ternary boride structure types, which are bmlt up of a rigid three-dimensional boron network, is given in Table 3. Many ternary boride phases also crystallize in the structure types collected in Table 3. It is noticeable that the B/M ratio ranges as much as from 2.5 to 66. 

The new complex ternary borides ThMB4, with M = Mo, W, V, or Re, have been obtained and shown to be isotypic.335... 

The ternary borides 75RU1 25B2 Ru)3B2 have been found to have the... 

Co-reduction of mixed oxides with metals (Mg or Al) in a thermite-type reaction — this usually gives contaminated products including ternary borides, e.g. M07AI6B7. Alternatively, alkali metals or Ca can be used as reduc-tants, e.g. 

Uranium-containing ternary borides UM64 (M = V, Cr, Mo, W, Mn, Re, Fe, or Co) have been prepared. Those for M = Mo, W, or Re have structures isotypic with ThMo64, while the others crystallize with the YCr64 structure. 

Some ternary borides, synthesized from the elements by argon arc melting, were characterized by X-ray powder diffraction data (Table lO.l.A). 

Table I0.1., Crystallographic data for ternary borides of technetium flOJ.

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