An intermediate method, Density Functional Tight Binding (DFTB) comes as a compromise between accuracy and efficiency. DFTB is a semi empirical quantum mechanical method, and approximates DFT by using pre-calculated parameters, a minimal basis, and including only nearest-neighbour interactions. DFTB has been extensively used on large biomolecules with accuracy comparable to DFT but is at least 2 orders of magnitude faster, not been used for MOFs because of the difficulty in parameterizationneeding to develop parameters for each pair of elements leads to ~100 2 required parameters. Consequently, while DFTB has been used extensively for Covalent Organic Frameworks, parameters have not been available for most MOFs.