Dimorphism in 4,4,6,6-tetra­chloro-2,2-(2,2-dimethyl­propane-1,3-di­oxy)cyclotriphosphazene and 6,6-di­chloro-2,2:4,4-bis­(2,2-dimethyl­propane-1,3-di­oxy)cyclotriphosphazene

A second, polymorphic, form of the previously reported compound 4,4,6,6-tetra­chloro-2,2-(2,2-dimethyl­propane-1,3-di­oxy)cyclotriphosphazene, C₅H₁₀Cl₄N₃O₂P₃, is now reported. The mol­ecular structures of these two compounds are similar, aside from minor conformational differences. However, the compounds crystallize in two different space groups and exhibit quite different crystal structure assemblies. Additionally, 6,6-dichloro-2,2:4,4-bis­(2,2-dimethyl­propane-1,3-dioxy)cyclotriphosphazene, C₁₀H₂₀Cl₂N₃O₄P₃, is shown to exhibit two different conformational polymorphs when crystallized from different solvent mixtures. The α form crystallizes in the space group Pnma with the mol­ecular structure lying on a mirror plane (symmetry code: x, −y + , z), whilst the β form is in the space group C2/c with the mol­ecular structure lying on a twofold axis (symmetry code: −x, y, −z + ). The difference between the two mol­ecular structures is in the conformation of the spiro-ring substituents with respect to the phosphazene ring. The resulting crystal structures give rise to differing packing motifs.

Polymorph VI of sulfapyridine: inter­penetrating two- and three-dimensional hydrogen-bonded nets formed from two tautomeric forms

Polymorph VI of 4-amino-N-(2-pyrid­yl)benzene­sulfonamide, C₁₁H₁₁N₃O₂S, is monoclinic (space group P2₁/n). The asymmetric unit contains two different tautomeric forms. The structure displays N—H...N and N—H...O hydrogen bonding. The two independent mol­ecules form two separate two- and three-dimensional hydrogen-bonded networks which inter­penetrate. The observed patterns of hydrogen bonding are analogous to those in polymorph I of sulfathia­zole.