Figure 2
The conformation of the acid H4A in II with the hydrogen bonds (dotted lines) it forms with the sulfate anions (displacement ellipsoids are drawn at the 30% probability level, C-bound H atoms are omitted for clarity). Symmetry codes: (i) −x + , y, −z + 1; (ii) x, −y + , z − ; (iii) −x + , −y + , −z + . |