Evidence of conglomerate with partial solid solutions in ethylammonium chlocyphos

We have established that ethylammonium chlocyphos also belongs to a family of conglomerate-forming systems composed of chlocyphos and alkyl-amine. The pure enantiomer and racemic mixture exhibit very close X-ray powder diffraction patterns but with some peak shifts. This led to consider that ethylammonium chlocyphos could crystallize as a conglomerate but with partial solid solutions close to the pure enantiomer. The crystal structures of the pure (S)- and (R)-ethylammonium chlocyphos have been solved using single crystal data. The temperature-composition binary phase diagram between the two enantiomers of ethylammonium chlocyphos system has been investigated to determine the limit of the solid solutions. This was confirmed by a Tammann plot related to the eutectic invariant characterizing the melting of the conglomerate. The limit of the composition range of the partial solid solutions was confirmed by X-ray powder diffraction measurements on different enantiomeric compositions.