During the synthesis of the (oxalato)[5,10,15,20-tetrakis(4-chlorophenyl)porphyrinato]magnesium(II) ([Mg(TClPP)(ox)]) complex [TClPP = 5,10,15,20-tetrakis(4-chlorophenyl)porphyrinate and ox = oxalate], the title compound, [Mg(C ₄₄ H ₂₄ ClMgN ₄ O ₂ )(H ₂ O) ₂ ] ([Mg(TClPP)(H ₂ O) ₂ ]), was obtained as a by-product. The diaqua–Mg ^II porphyrin complex crystallizes in the I 4/ m space group. In the asymmetric unit, except for two carbon atoms of the phenyl ring, all atoms lie on special positions. In the crystal, the [Mg(TClPP)(H ₂ O) ₂ ] molecules form layers parallel to the a axis. The crystal packing features C—H...π interactions involving the pyrrole rings and non-conventional O—H...Cl hydrogen bonds between the oxygen atom of the water axial ligands and the chloride of neighboring phenyl groups. Hirshfeld surface analysis indicates that intermolecular contacts are dominated by H...H (50.2%), followed by H...Cl (21.6%) and H...C (21.2%) interactions, then by less chemically meaningful C...Cl (6.0%) contacts.

Maxwell's electric equation and Schrödinger quantum equation are used to find useful expressions for the probability of electrons existence and the electrons transport. The first expression which uses special relatively also shows that the probability of the electrons existence is higher for lower energy states compared to higher energy states where the probability is low. This means that electrons transport takes place from higher energy states to lower states. This conforms to the laws of chemistry where the atom tends to be stable by forcing electrons to occupy lower energy states. The second expression used the momentum velocity relation instead of special relatively. This expression shows also electrons transport from higher to lower states. It also shows that the probability of the electrons existence is higher for lower electrons density regions and lower for higher electrons density regions. This means that the electrons transport is from higher density regions to lower density regions. This conforms to the diffusion law.