| abstract |
A large single crystal of a complex such as an organic carboxylic acid metal complex, which crystal is useful as an adsorbent of various gases and vapors of organic solvents and as a hydrogen-absorbing material, as well as a process for producing the crystal, is disclosed. Two layers wherein an upper layer thereof is constituted by a solution containing a metal salt and an organic carboxylic acid having a conjugated system, or a solution containing a metal salt of the organic carboxylic acid having a conjugated system, and wherein a lower layer of the two layers is constituted by a solvent which is not miscible with the solvent of the solution, is formed. Vapor of pyrazine or a substituted pyrazine from a solution of pyrazine or the substituted pyrazine is introduced into the upper layer to allow reaction, thereby forming a large single crystal(s) of the organic carboxylic acid metal complex at the interface between the two layers, which crystal(s) has(have) a longer side with a size of not less than 0.8 mm. |