Tetragonal compounds

The Tetragonal Compound LigAISis, a Good Anodic Material... 

Out of 17157 point sets investigated, 83% (14 194) belong to one of these 23 AET. Of the 4264 compounds crystallizing in one of the mentioned 294 structure types, 16% belong to a single-environment group (that is to structures in which all atoms have the same type of environment) 17% combine two environment types 42% three 13% four and the rest (12%) five or more (88% of the tetragonal compounds crystallize in structure types with 1, 2, 3 or 4 AET). 

Metals Co fee — hep Hg rhombohedral — body-centred tetragonal. Compounds ZrOy. tetrag. — monoclinic Si02 rhomboh. — hex. MnS ZnS type — NaCl type. 

As an aside, it is interesting to note that the tetragonal compound FcNiN can be prepared. From the model, it was predicted that the compound should be ordered into alternate Fe and Ni layers perpendicular to the c axis with the N atoms filling all the octahedral interstices of the Fc layers. (The filled d - orbitals at the Ni atoms prevent occupation of the octahedral sites in a Ni layer.) This atomic ordering was indeed found. Further, with all localized electrons spin-paired, the compound is paramagnetic (224). 

Tetragonal compounds oftheUX2 andUXY type, again PuS fee Fmim 5.537 ... 

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