The monoclinic crystals of the isomorphous compounds with general formula [ Me (II)(N 2 H 4 ) 2 ]Cl 2 , where Me (II) = Cd, Zn, Mn, form twins according to different laws. The twin law (001) was observed in crystals of [Cd(N 2 H 4 ) 2 ]Cl 2 , of [Zn(N 2 H 4 ) 2 ]Cl 2 and of [Mn[N 2 H 4 ) 2 ]Cl 2 ; the twin law (110) in crystals of [Cd(N 2 H 4 ) 2 ]Cl 2 and of [Mn(N 2 H 4 ) 2 ]Cl 2 ; the twin law (100) only in crystals of [Mn(N 2 H 4 ) 2 ]Cl 2 . Twinning was deduced from Weissenberg photographs, taking into account the symmetries of the reciprocal layers of the twins. A large number of crystals was examined and their statistical distribution over the twin laws was calculated. The compounds can be assigned to the possible space groups C 2 h 3 – C 2/ m ; C 2 3 – C 2; C s 3 – Cm . From the dimensions of the unit cells it can bo inferred that molecules of hydrazine form bridge-complexes between two metal-ions, as in the compounds with general formula [ Me (II)(N 2 H 4 ) 2 ](NCS) 2 . Obliquities of the twins and twin indices were calculated. Due to the geometrical rather than structural character of the quasi-normal axis, no sure relation can be found between the obliquities, or the twin indices, and the statistical frequencies with which the twin laws appear. More likely the formation of the twins is due to chains of bridge complexes [unk], which form “clusters“ opposing the adjustment of single atoms in the previous structure.
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Erfordert eine Authentifizierung Nicht lizenziertTwinning in crystals of the isomorphous compounds [Me(II)(N2H4)2]Cl2Lizenziert28. Juli 2010
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Erfordert eine Authentifizierung Nicht lizenziert“Nahezu-homometrische Lösungen” und FaltmolekülmethodeLizenziert28. Juli 2010
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Erfordert eine Authentifizierung Nicht lizenziertLattice constants and thermal-expansion properties of the chromates and selenates of lead, strontium and bariumLizenziert28. Juli 2010
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Erfordert eine Authentifizierung Nicht lizenziertThe crystal and molecular structure of echitamine iodide, C22H29O4N2ILizenziert28. Juli 2010
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Erfordert eine Authentifizierung Nicht lizenziertA refinement of the crystal structure of galliumLizenziert28. Juli 2010
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Erfordert eine Authentifizierung Nicht lizenziertAusnutzung des Dichroismus zur Orientierung von Kristallen*Lizenziert28. Juli 2010
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Erfordert eine Authentifizierung Nicht lizenziertSingle crystal x-ray study of structural polytypism in cadmium bromideLizenziert28. Juli 2010
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Erfordert eine Authentifizierung Nicht lizenziertAn x-ray study of meta chloronitrobenzeneLizenziert28. Juli 2010