The thermal stability of Oxo salts are increase as we move down to the group for alkali and alkaline earth metals because increase the size of cation and decreases its polarizing power. This leaves the six-membered ring as a compromise for MgO systems. [52]. and Carbonate ion is so large that relatively small changes in the size of the cation from Be2+ to Ba2+ do not make any difference. This structure has a high band gap (3.05 eV), which is much lower than that reported for bulk MgO [45–47]. These have high melting point, have very low vapour pressure, are very good conducts of heat, are … An explanation based on packing and aromaticity arguments has been proposed. The peak height for the slab structure is also smaller. In contrast, the slab structures are slightly preferred for the other alkaline metal oxide (MO)6 clusters. The increased charge separation in the interior has only a minor effect on the terminal rings beyond that already seen for the double-ring (MgO)4 system (1.943 Å). MgCO3 +Heat -> MgO +CO2. Though the GGA-PW91 value (4.55 eV) is in slightly better agreement with experiment, the LDA Ca–O bond distance (1.818 Å) is in excellent agreement with the experimental [43] value (1.822 Å), while the GGA value is considerably larger (1.843 Å), reflecting the tendency of GGA to underbind. Here, again, our LDA result shows the best correspondence with experiment. The stability of carbonates and bicarbonates increases down the group. For Ritu Gaba and Upasana Issar thank the CSIR and the University Grants Commission (UGC), respectively, for Senior Research Fellowships. The inner ring bond distance is also only slightly larger than the bulk value for the (MgO)6 slab, and the deviation from the bulk value increases with increasing atomic number of the metal, suggesting a faster overall convergence to bulk properties for MgO clusters than for other alkaline metal oxide clusters. Down the group thermal stability of nitrates increases. Explanations based on ionic size effects and aromaticity have been proposed in this work. The largest number of structures is possible in this case, namely, ladder, hexagonal, decagonal, chair, and many others (Table 3). 900 0 C) The greater the polarization of the carbonate ion, the easier it is to weaken a carbon-oxygen bond in the carbonate and form carbon dioxide and the oxide in heating. Nitrates of alkaline and alkali metals give corresponding nitrites except for lithium nitrate, it gives lithium oxides. As the cluster size increases, the bond lengths and binding energies increase in an oscillatory manner. The energy differences are higher for this case, and the slab form is more emphatically preferred. The high surface area and the intrinsically high surface reactivity of MgO nanocrystals make these materials especially effective as adsorbents [6]. The increasing order of the cationic size of the given alkaline earth metals is. Peroxides are formed with increasing ease and increasing stability as the metal ions become larger. , there is a consistent preference for slab-shaped structures, but the stability difference between the most stable and the second most stable structure is always small. For (CaO)3, however, it was found that both initial structures optimized to different geometries. Various structures, including the slab, hexagonal, octagonal, ladder, and other types, were studied for various numbers of formula units of the four alkaline earth metal oxides. Their structures are usually inferred indirectly from the mass spectra of ionized clusters, the more abundant species being interpreted as the more stable. The bond length is elongated to 1.882 Å in the most favorable structure of (MgO)2, which is a rhombus. It is considered as a prototype oxide from the theoretical point of view, with a wide band gap (7.1 eV) [10] and a high dielectric constant (11.8). Thermal stability: Increases down the group like carbonates BeSO 4