Pseudo-ternary compounds

Figure 1 Four examples of cluster structures (a) Na2[Pt3(CO)6] ( = 2,3,5) inset TEM picture of Pt nanoparticles from [Pt3(CO)e]fo precursor (b) unit cell of Pt2Ru4(CO)is cluster. Coordination distances in a cluster are i pt Ru = 2.70 A, = 2.66 A, and Rru.ru = 2.16 A (c) unit cell of Ru4Se2(CO)n cluster. Coordination distances in a cluster are Rru-ru = 2.79 2.77 A, i Ru-se = 2.56 2.60 A. Inset TEM picture of Ru Se, colloidal nanoparticles from Ru3(CO)i2 and Se, via the Ru4Se2(CO)n chemical precursor (the stabilizer was octade-canthiol) (d) Chevrel cluster phase MoeScg. Coordination distances in a cluster are Rmo-mo = 2.68 2.83 a, and RMo-se = 2.598 A. For a pseudo-ternary compound Mo4Ru2Ses. Coordination distances in a cluster are 7 Me-Me = 2.659, 2.71 A i Me-se = 2.623 A.

The magnetic properties of the pseudo-ternary compounds (Y1 xNdx)2Co14B were studied by Kakol et al. (1987). From the non-linear increase of Kx with Nd concentration the authors conclude to the presence of an anisotropic exchange interaction that contributes to the Nd sublattice anisotropy. 

Figure 4. Idealized pseudo-ternary phase diagram for the Si02 Cu0-BaO system, showing only the solid phases. The tie-lines were drawn based on the assumption that no pseudo-ternary compounds form.

Not truly a heavy-fermion system but used as endpoint in series of pseudo-ternary compounds. 

The series CeTSn together with CeRhSb and the related pseudo-ternary compounds crystallize in a rather complex orthorhombic structure with the non-centrosymmetric space group Pn2ia (Higashi et al. 1993). This structure, which is shown in fig. 106 (left), is closely related to the e-TiNiSi structure. It forms puckered hexagonal Ni—Sn-Ni rings... 

Characteristic for the series, including pseudo-ternary compounds, is the change in unit cell volume when varying the T elements. Some pertinent data are summarized in table 13. This change in unit cell volume has strong effects on the electronic structure of these intermetallics. For example, CeNiSn does not order magnetically, as proven in particular by (xSR data, while CePtSn and CePdSn show AFM order with transition temperatures... 

Compounds made by insertion at room temperature are often metastable - if heated, they change their structure or decompose into other compounds. That does not rule out using thermodynamics it just means that processes happening slowly compared to the duration of an experiment are assumed to be frozen. At room temperature, the ratio of Mo to Se in a host like Mo Seg is fixed. From the point of view of thermodynamics, the constraint that the host remain Mo Seg means that we can regard an intercalation compound like Li -MogSeg as a pseudo-binary compound instead of a ternary one. 

Fig. 2.83 Pseudo-ternary Fe2O3 BaFe2O4-Me Fe2O4 system. Compounds labelled M, Y, and W have the compositions BaO-6Fe2O3, BaO MeO 3Fe2O, and BaO-2MeO-8Fe2O3, respectively.

Schomacker compared the use of nonionic microemulsions with phase transfer catalysis for several different types of organic reactions and concluded that the former was more laborious since the pseudo-ternary phase diagram of the system had to be determined and the reaction temperature needed to be carefully monitored [13,29]. The main advantage of the microemulsion route for industrial use is related to the ecotoxicity of the effluent. Whereas nonionic surfactants are considered relatively harmless, quaternary ammonium compounds exhibit considerable fish toxicity. 

Ternary compounds differ from pseudo-binary compounds in that the different crystallographic sites are occupied by different types of atoms. In general, one might say that the physical properties of pseudo-binaries can be described by a weighted mean of the properties of the parent binary compounds from which they are derived. This is no longer true for ternary compounds. Here one may expect novel properties not found in binary compounds. Very often also the crystal structure and the formula composition have no analogue in the corresponding binary systems. Up to now, systematic experimental studies as to the occurrence of ternary compounds... 

Figure 5. The boundary of the pseudo-ternary phase diagram for foe Si02-Ba0-Y203 system. Since it is almost certain foat pseudoternary compounds exist in this system, no attempt has been made to estimate the positions of the tie-lines.

The first 5 materials are pseudo-binary or ternary compounds based on established HF or Kondo-lattice materials. The last 3 are independent intermetallics on their own for which NFL behavior has been claimed. 

The platinum group metals form several binary, pseudo-binary, and ternary chalcogenides. The outstanding features of these compounds as related to catalysis and materials science have been widely reported and reviewed [88],... 

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