Indium lattice structure

The telluride halides crystallize in monoclinic lattices, but only In-TeBr and InTel are isotypic 162). InTeCl forms a layer type of structure, as do InSCl and its analogs, but, owing to the size of the Te atom and the enhanced covalency of the In-Te bond, only a coordination number of 4 for indium is realized. The structure is built up of strongly distorted, InTesraCli/j tetrahedra that share the corners and edges occupied by Te atoms. The Cl atoms are coordinated to one tetrahedron each, and do not take part in the layer formation 324, 325). 

Electrolysis in the cell Pt/MeC02H H20(trace)/In caused dissolution of the indium anode and formation of fine feathery crystals of the metal on the cathode. This material slowly reacted with the electrolyte to give crystals of In(OAc)2 which could be converted to In(OAc)3 on boiling with glacial acetic acid. It seems likely that the crystal lattice consists of In1 4- In111 + OAc-, but no detailed structure could be obtained.31 This system warrants further investigation in view of work on the analogous thallium system (see below). 

A] bond distances. The restricted bite distances of the xanthate ligands [the S—M—S chelate angles are 73.50(6) and 69.77(4)°, respectively] are most the likely source for the deviations from the ideal octahedral geometries. The distortions are best seen in the twists of the triangular faces, that is, 40.27(7) and 46.43(5)° for the gallium and indium structures, respectively, compared to the ideal octahedral angle of 60°. Enantiomeric pairs associate in their respective crystal lattices via S- -S contacts of 3.598(4) and 3.592(2) A, respectively. 

In the absence of good quality single crystal samples, the physical properties of indium nitride have been measured on non-ideal thin films, typically ordered polycrystalline material with crystallites in the 50 nm to 500 nm range. Structural, mechanical and thermal properties have only been reported for epitaxial films on non-lattice-matched substrates. 

Clusters of the semiconductor elements Si and Ge are much more dense than carbon clusters, but they are not spherical, either, as expected for closed packed atomic spheres. Si+ and Ge+ clusters are prolate with geometries based on stacked tricapped trigonal prisms [127-131]. At a certain cluster size (n 25 for SiJ) a structural transition occurs from prolate (n<25) to near spherical (n>25). Interestingly, clusters of tin, which is a metal at room temperature, exhibit very similar structures as Si and Ge, indicating that they are semiconductors as well [131,132]. Bulk Sn does have a semiconductor form (a-tin), that has the same diamond lattice as Si and Ge. Typical metal clusters appear to pack as tightly as possible and exhibit near spherical shapes as observed for the lead [131,133],indium [134],andgold [135] clusters. However, the smaller gold clusters AuJ (n<7) are completely planar [135]. 

An extended material of valence electron spatial correlations (VEC) had been analyzed (Schubert, 1964), when it became apparent that one correlation of valence electrons alone is not sufficient for the explanation of crystal structures of metallic phases. The outer core electrons had to be taken into consideration. This may best be seen from the crystal structure of indium (Fig. 4) The lattice matrix of In may be given in diagonal form ai = (4.59 4.59 4.95) A. The explicit lattice constants are needed for verification that the proposed VEC is acceptable. The VEC is aj = aAi(l, —1,0 1,1,0 0,0,3/2) and may be decomposed into the equations at = a j + a2 a2 = - aj + a2 a3 = 3 a3/2, which may be verified by means of Fig. 4. If a correlation lattice is inserted into a crystal structure, this does not mean that there are positions of increased electron density in the cell, it only gives the commensurability which is favorable energetically. It is easily verified that the number of valence electron places per cell is = 12 and is equal to the number of valence electrons in the cell given above = 12. The A1 type of the VEC had been inferred from the diamond struc-... 

The complete X-ray powder pattern of InSe, not previously published, has been indexed " on the basis of a layer structure in the space group R3m, with ao = 4.0046, Co = 25.960 A. The effects of various heat treatments on the powder patterns were discussed. A crystal-structure determination has given the same space group, with the lattice constants ao = 4.00 and Co = 25.32 A. The structure can be considered as being formed of double layers of selenium atoms, parallel to the (001) plane, between which occur pairs of indium atoms. 

Of the group 13 metals, only A1 reacts directly with N2 (at 1020K) to form a nitride AIN has a wurtzite lattice and is hydrolysed to NH3 by hot dilute alkali. Gallium and indium nitrides also crystallize with the wurtzite structure, and are more reactive than their B or A1 counterparts. The importance of the group 13 metal nitrides, and of the related... 

The experimental values of the structure amplitudes, determined in earlier investigations, were used to find the electron density distribution in the indium phosphide lattice. Electron density "bridges, whose density was at least 0.35 1 0.05 electron/A were found between the nearest unlike atoms. The signs and the effective charges of the atoms (0.40 0.15 el) were determined. 

Extensive regions of homogeneous solid solutions close to indium arsenide were established by physicochemical methods of analysis in the following quaternary systems InAs-CdS, InAs-CdSe, InAs-CdTe, InAs-ZnS, InAs-ZnSe, InAs-ZnTe. All the melts crystallize in the sphalerite structure and exhibit a linear relationship between the lattice constant and composition. The results ate presented of studies of the electrical conductivity, the Hall effect, and the thermoelectric power, and of electron-microscope studies of the cleaved surfaces of the alloys. 

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