Manganese structure

Hume-Rothery and Bradley have mentioned that the a manganese structure can be explained only by assuming that the atoms are of different sixes (/. Inst, Metals, 11,252,257 (1944)). 

Table III. X-ray reflection data for /3-manganese structure (AgsAl) and calculated electron densities.

It was reported by Fagerberg and Westgren20 that the compound CoZn3 also crystallizes with the /3-manganese structure. The electron number... 

It was pointed out by Bradley and by Hume-Rothery22 that the nature of the a-manganese structure suggests that there are manganese atoms present of two different sizes, and a study... 

The /3-alloys are different in nature from the 7-alloys and the a-manganese and /3-manganese structures discussed above, in that they are not complex structures, but are simple, being based upon the body-centered arrangement. /3-Brass, for example, has either a disordered structure, above 480°K, the copper and zinc atoms in essentially equal number being distributed largely at random over the points of a body-centered cubic lattice, or an ordered structure, below 300°K, with copper and zinc at the positions 000 and, respectively, of the cubic unit. Moreover, the physical properties of /3-brass are not those that indicate a filled zone structure. 

Tazaki, K. (2000) Formation of banded iron-manganese structures by natural microbial communities. Clays Clay Min. 48 511-520... 

The compound Mg Al-u crystallizes with the a-manganese structure, and several compounds (Ag Al, Cu Si) have the 0-manganese structure, with some randomness of distribution of atoms of different kinds over the two kinds of atomic positions. 

No binary xanthate structures of manganese, technetium, or rhenium have been reported. Indeed, there are relatively few crystal structures known with only a single manganese structure (two polymorphs), two phosphine adducts of technetium and three structures containing rhenium, two of which are dinuclear. 

EPR data from S0) Si, and S2 indicate that there are coupled Mn ions. In particular, the multiline signals are suggestive of coupled manganese structures that require clusters of greater than two manganese ions. 

Electron atom ratio - 3 2 Body-centered Complex cubic cubic structure (/l-manganese) structure Oose-packed hexagonal structure Electron atmn ratio = 21 13 y-brass structure Electron atom ratio = 7 4 Close packed hexagonal structure... 

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