Reaction Calculator Manual

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Contents

Overview

The reaction calculator allows users to estimate tens of thousands solid-state reaction enthalpies from a database of density functional theory calculations. In addition, the reaction calculator reports known experimental enthalpies (at 298K and 1atm) where available.

The reaction calculator's energies are generally a good estimate of room temperature formation enthalpies, although all calculations are performed at 0K and 0atm. More information regarding methods to perform the calculations and their accuracy can be found in the Calculations Manual.

Using the Reaction Calculator

To use the reaction calculator, the reactants input and products input fields must be completed. Other fields are optional. Multiple advanced arguments may be specified by comma-separating each argument.

Specifying Reactants and Products

Reactants and Products are specified via chemical formula in the free-form text fields. Chemical formulas must be "+"-separated. The coefficients of all compounds are automatically determined; there is no need for the user to balance the reaction.

For each chemical formula, our database automatically selects the lowest energy compound at the specified composition (handling of gaseous and liquid elements is explained in the Calculations Manual). The crystal structure used for a particular reaction calculation may be examined by clicking the blue links in the reaction output.

There are several ways of specifying the chemical formula (examples follow). In all cases, element names should have only the first letter capitalized.

The reaction energy will always be normalized for the reaction shown in the output.

Choosing a particular phase / crystal structure

This feature will be supported in a future release of the reaction calculator.

Reading the output

The reaction calculator balances the reaction and displays the balanced reaction as the first line in the output. The next line gives the computed reaction energy.

When a computational energy is available, the computed ΔH of reaction indicates the overall reaction energy of the reaction as written in the first line of the output. The ΔHf for each compound in the reaction lists formation energies from the elements. Clicking the compound displays its crystal structure.

When an experimental energy is available, the computed ΔH of reaction indicates the overall reaction enthalpy of the reaction as written in the first line of the output. The ΔHf for each compound in the reaction lists formation enthalpies from the elements. Sub-headings indicate the source(s) of experimental information.

When both computational and experimental data are available, a graphical chart displays the error for each compound in the calculation.

Calculation Details / Estimating Errors

The Calculations Manual provides details on our calculation methodology and provides information on the magnitude of errors that may be expected.

Citation

To cite the reaction calculator, please reference the following works:

Authors

  1. Anubhav Jain
  2. Shyue Ping Ong
  3. Charles Moore
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