title: Microsolvation and hydration enthalpies of CaC₂O₄(H₂O) n (n=0-16) and C₂O₄²⁻(H₂O) n (n=0-14): an ab initio study.
abstract: We studied hydrated calcium oxalate and its ions at the restricted Hartree-Fock RHF/6-31G* level of theory. Performing a configurational search seems to improve the fit of the HF/6-31G* level to experimental data. The first solvation shell of calcium oxalate contains 13 water molecules, while the first solvation shell of oxalate ion is formed by 14 water molecules. The first solvation shell of Ca(II) is formed by six water molecules, while the second shell contains five. At 298.15 K, we estimate the asymptotic limits (infinite dilution) of the total standard enthalpies of hydration for Ca(II), oxalate ion and calcium oxalate as -480.78, -302.78 and -312.73 kcal mol(-1), resp. The dissociation of hydrated calcium oxalate is an endothermic process with an asymptotic limit of +470.84 kcal mol(-1).
authors.affiliation: Facultad de Ciencias Químicas, Universidad Autónoma de Nuevo León, Ave. Pedro de Alba S/N, Ciudad Universitaria, San Nicolás de los Garza, N L, Mexico 66451. rosas.victor@gmail.com
authors.forename: Victor M
authors.initials: VM
authors.lastname: Rosas-García
authors.forename: Isabel
authors.initials: I
authors.lastname: del Carmen Sáenz-Tavera
authors.forename: Verónica Janeth
authors.initials: VJ
authors.lastname: Rodríguez-Herrera
authors.forename: Benjamín Raymundo
authors.initials: BR
authors.lastname: Garza-Campos
mesh_terms: D002129:Calcium Oxalate / Q000737:chemistry*; D006801:Humans; D007669:Kidney Calculi / Q000737:chemistry; D008956:Models, Chemical; D011789:Quantum Theory; D012996:Solutions; D013816:Thermodynamics; D014867:Water / Q000737:chemistry*
chemical_list: D012996:Solutions; D014867:Water; D002129:Calcium Oxalate