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Application of the PM6 method to modeling the solid state.

Stewart JJ - J Mol Model (2008)

Bottom Line: The applicability of the recently developed PM6 method for modeling various properties of a wide range of organic and inorganic crystalline solids has been investigated.Although the geometries of most systems examined were reproduced with good accuracy, severe errors were found in the predicted structures of a small number of solids.The origin of these errors was investigated, and a strategy for improving the method proposed.

View Article: PubMed Central - PubMed

Affiliation: Stewart Computational Chemistry, 15210 Paddington Circle, Colorado Springs, CO 80921, USA. MrMOPAC@OpenMOPAC.net

ABSTRACT
The applicability of the recently developed PM6 method for modeling various properties of a wide range of organic and inorganic crystalline solids has been investigated. Although the geometries of most systems examined were reproduced with good accuracy, severe errors were found in the predicted structures of a small number of solids. The origin of these errors was investigated, and a strategy for improving the method proposed.

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Unit cell of parahilgardite. Crossed-eyes stereo view
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Fig12: Unit cell of parahilgardite. Crossed-eyes stereo view

Mentions: Several borates were examined, including the simple sodium salt, borax. Like other solids that contain a large amount of sodium, its optimized PM6 structure was severely in error. With that single exception, the structures of the borates were reproduced with good accuracy. Almost all minerals have some symmetry in their unit cell, the most well known exception being the naturally-occurring calcium chloroborate, parahilgardite, Ca2(B5O9)Cl(H2O). PM6 was able to reproduce the unit cell of this almost unique mineral with good accuracy, despite the fact that the unit cell was completely devoid of any symmetry (Fig. 12). This system was unique among the solids studied in that, unlike all the organic compounds, there were no readily identifiable discrete molecular fragments, and, unlike the other inorganic solids, it is devoid of any elements of symmetry.Fig. 12


Application of the PM6 method to modeling the solid state.

Stewart JJ - J Mol Model (2008)

Unit cell of parahilgardite. Crossed-eyes stereo view
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2386531&req=5

Fig12: Unit cell of parahilgardite. Crossed-eyes stereo view
Mentions: Several borates were examined, including the simple sodium salt, borax. Like other solids that contain a large amount of sodium, its optimized PM6 structure was severely in error. With that single exception, the structures of the borates were reproduced with good accuracy. Almost all minerals have some symmetry in their unit cell, the most well known exception being the naturally-occurring calcium chloroborate, parahilgardite, Ca2(B5O9)Cl(H2O). PM6 was able to reproduce the unit cell of this almost unique mineral with good accuracy, despite the fact that the unit cell was completely devoid of any symmetry (Fig. 12). This system was unique among the solids studied in that, unlike all the organic compounds, there were no readily identifiable discrete molecular fragments, and, unlike the other inorganic solids, it is devoid of any elements of symmetry.Fig. 12

Bottom Line: The applicability of the recently developed PM6 method for modeling various properties of a wide range of organic and inorganic crystalline solids has been investigated.Although the geometries of most systems examined were reproduced with good accuracy, severe errors were found in the predicted structures of a small number of solids.The origin of these errors was investigated, and a strategy for improving the method proposed.

View Article: PubMed Central - PubMed

Affiliation: Stewart Computational Chemistry, 15210 Paddington Circle, Colorado Springs, CO 80921, USA. MrMOPAC@OpenMOPAC.net

ABSTRACT
The applicability of the recently developed PM6 method for modeling various properties of a wide range of organic and inorganic crystalline solids has been investigated. Although the geometries of most systems examined were reproduced with good accuracy, severe errors were found in the predicted structures of a small number of solids. The origin of these errors was investigated, and a strategy for improving the method proposed.

Show MeSH
Related in: MedlinePlus