Binary structures structural types

Analysis of the dependence of the behaviour of alloy systems on the properties of the component elements. In an examination of the binary structure types containing more than five representatives, Villars and Girgis (1982) observed that 85% exhibited the following regularities ... 

Interconnection of the ternary antimonides with the binary structure types 140... 

Table 4 demonstrates the superstructures which are formed as a result of an ordered substitution of the smallest atoms in the initial binary structure type by the other small atoms. 

The structure type Y3NiAl3Ge2 is an example of a quaternary substitution variant of a binary structure type Fe2P —> ZrNiAl —> Y3NiAl3Ge2 (SG P62m). The partly ordered occupation of the atomic positions of Be in the CaBe2Ge2 structure by the transition metal atoms leads to the formation of the LaPti.42Pdo.5sGe2 superstructure. 

The next three compounds TmjNinGe, EuCo2Ga3 and CcjNiGcj are formed as a result of an ordered substitution of the smallest atoms in the initial binary structure types by the smallest ones in the resulting superstructures. The initial binary types are EuMgj, BaZn and Ndjirj, respectively. This type of substitution (small atoms by small ones) is well-known for different kinds of inter-metallics. 

Here the structures which may be considered filled-up versions of binary structure types can be also included (see, for example, GdjNiSij shown in Fig. 9). There remain, however, many ternary structures for which no binary analogues can be found. 

The three binary structure types NaP Zni3, Bal Cdn and Th iMnij differ in the number of atoms in the coordination polyhedron around the minority component. 

Binary structure type Code of ternary compound Compound Pearson s classif. symbol Space group R-Fe-AI R-Co-Si... 

By the end of 1982 we know more than 1650 R-T-M compounds, which crystallize with more than 120 structure types. Less than half of these types can be described as ternary derivatives of binary structure types. The number of R-T-M compounds known for each structure type and a simple classification of the elements present in these compounds is given in condensed form in table 23. 

Code R-T-M compound discussed in the text Ternary structure type Related binary structure type Pearson st classif. symbol Space group g a 2 rt o> 0 C/3... 

Structure type Boron coordination Binary representative... 

Binary and ternary structure types with isolated B atoms are listed in Table 1. In the metal borides of the formula (My, Mi ),B or T,(B, E) (M-p, M - = transition metals, E = nonmetal), the influence of the radius ratio as well as the... 

Structure type Binary representatives Ternary representatives. Boron coordination Type of boron defects... 

Boron atoms in infinite boron zigzag chains form covalent B—B bonds at 165-190 pm with bond angles of 115°. The boron coordination is trigonal prismatic, giving rise to coordinated rows of face-connected trigonal metal prisms (Table 1). Most typical are the binary transition-metal monoborides such as the FeB, CrB and MoB structure types. Transformations between pairs by simple geometric shifts ... 

Structure type Boron aggregation boron coordination Binary representatives Ternary representatives Refe. 

Four simple crystal structural types encompass the majority of elemental or binary semiconductors. The high symmetry of the structures has important consequences for the NMR spectra in several respects ... 

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