![]() Molecular geometry is a way of describing the shapes of molecules. Similar logic applies to all the shapes, you just have to remember which "spoke" will be taken up by an electron pair. Once there are any electron pairs, one spoke of the original shape gets "eaten up": for example, a #AX_4E_2# is an octahedron shape, but the two "spokes" are taken up by electron pairs, so you're left with just the square-a square planar shape. #6#: octahedron (a flat square with two "spokes") #5#: trigonal bipyramid (a trigonal planar shape with two "spokes") #3#: trigonal plane (a flat equilateral-triangle-looking shape) As it has a VSEPR shape #AX_5E_0# it is a trigonal bipyramid.Įach steric number has a same "basic shape": Its steric number is #5# due to the #5# bonded atoms to the central #S# atom plus #0# lone electron pairs. Thus, it is in the form #AX_3E_1#, which forms a trigonal pyramidal shape. #N#, the central atom, has a steric number of #4#, calculated by the #3# atoms it's bonding with #+1# lone pair. ![]() This is the total number of electron pairs and bonds with other atoms. "This means that there is a chance that maleate could be degraded by certain substances," says Savchenko.Find the central molecules' steric numbers. Fumarate and succinate, on the other hand, could be more stable, as their HOMO orbitals are equally delocalised. What's more: The analysis also explains why: The electronic density in the HOMO orbital at the C=C bond between carboxylate groups could lead to weaker binding of maleate with molecules or ions. The analysis of the spectral data shows that maleate is potentially less stable than fumarate and succinate. The results can be related to macroscopic properties, especially stability. X-ray absorption spectroscopy (XAS) can be used to investigate the unoccupied electronic states of a system, while resonant inelastic X-ray scattering (RIXS) provides information about the occupied highest orbitals and about interactions between the HOMO-LUMO orbitals. "We analysed these compounds at BESSY II with two different, very powerful methods," says Dr Viktoriia Savchenko, first author of the study. Alexander Föhlisch has elucidated the influence of the electronic structure on the stability of fumarate, maleate and succinate dianions. However, the influence of the molecular orbitals on stability of these molecules has not been researched. ![]() The stability of fumarate, maleate and succinate dianions is not only influenced by their molecular geometries, but also by the electronic structure of the molecules, in particular the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO). For environmental reasons, however, the question arises as to whether these compounds last forever or are biodegradable. Maleate, on the other hand, which is usually not formed in natural processes, is used in industrial applications that require durable materials. Fumarate and succinate, for example, are formed as intermediate products in the mitochondria of cells. Some variants are key in coordination chemistry, incorporating metallic elements into organic compounds, other variants play a role in biological processes. Carboxylic acid dianions of the type C 4H 2O 4 or C 4H 4O 4 (fumarate, maleate and succinate) can have different geometries (cis or trans) and different properties. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |