A. R. Zanzari

The crystal structure of a triclinic roscherite

The crystallography of roscherite is more complicated than previously thought. Single crystal X-ray work on material from Foote Mine (California) gave triclinic symmetry. The unit cell corresponding to the one adopted for monoclinic roscherite hasa=15.921,b=11.965,c=6.741 A, α=91°04′, β=94°21′, γ=89°59 1/2′, space group

Theoretical structures of pyridazino[4,5-d]pyridazine and 1,4,5,8-tetramethoxypyridazino[4,5-d]pyridazine

C\bar 1

The crystal and molecular structure of 4'-methylene-1,2-di-m-bromophenyl-1',2',6',7'-tetraphenylspiro{pyrazolidine-4,8'-[8'H,4'H]-benzo[1,2-c:4,5-c']dipyrazoline}-3,5,3',5'-tetraone, C47H30N6O4Br2

. The least-squares refinement of the structure using 2380 non zero reflections with anisotropic temperature factors resulted in a conventional reliability factorR=0.060. The X-ray study indicates the formula

Die Kristallstruktur eines triklinen Roscherites

(Me_{{2 \mathord{\left/ {\vphantom {2 3}} \right. \kern-\nulldelimiterspace} 3}}^{3 + } \square _{{1 \mathord{\left/ {\vphantom {1 3}} \right. \kern-\nulldelimiterspace} 3}} )\square _1 Ca_2 Me_4^{2 + } Be_4 (PO_4 )_6 (OH)_4 \cdot 6H_2 O

Die Kristallstruktur des Roscherits

while that proposed for monoclinic roscherite is