For the first time the carbene character of a formyl anion equivalent can be demonstrated in the crystal structure of the title compound 1. A comparison of the structures of thiazole, the stable nucleophilic carbene 2 (both accessible experimentally), and LiCHO (calculated) leads to this result. Furthermore, 1 is yet another example of complexes of nucleophilic carbenes with Lewis acids, which have aroused great interest lately. (Figure Presented.) Copyright © 1995 by VCH Verlagsgesellschaft mbH, Germany