Materials Project Database Release Log

We’ve released a new revision of the Materials Project database as part of a major overhaul of our software infrastructure. This enables us to continue to build new properties and deliver them to you, the material science community, at an accelerating pace. This has also caused some growing pains as we fix bugs we created in building our new infrastructure from scratch.

Many of our users have reported bugs, and we are very grateful for that. We’re making great strides in being as transparent as possible so everyone knows what is changing. As part of this, we’ve settled on a monthly release schedule including an announcement that informs everyone on what has or has not changed.


  • Introduced a new deprecated field to materials. By default the website and API only search for materials that are not deprecated: {“deprecated”: false}.
  • Deprecated 15,000 and added 3,600 new materials. We will be recomputing the deprecated materials to fill these spaces back up. Some of these new relaxations may end up matching current materials, so the total number of materials is not guaranteed to be the same as in V2019.02.
  • Fixed an issue with sandboxes not properly building the whole hull. Previously, only the sandboxed chemical systems were being recalculated for energy_above_hull searches


  • Added over 47,000 new materials from orderings of disordered ICSD as well as compounds from the Pauling File
  • Finalized enforcing symmetry on piezo tensors
  • Moved third order elastic data to elasticity_third_order so that people are not swamped by the mountain of information associated with it.


  • Adjusted the mp-id naming scheme to fix “mvc” ids taking over old mp-ids.
  • Fixed piezoeletric max_direction to be a miller index rather than a unit vector.


  • Changed the grouping of magnetic materials to aggregate all magnetic orderings of a given material into a single material-id, and report the lowest energy ordering
  • Fixed incorrect calculation and display of polycrystalline dielectric constants
  • Fixed labeling of all materials as high-pressure. Note we’re parsing ICSD tags for this labeling so while some materials may not conventionally be considerd high-pressure, a single matching ICSD entry can tag a material as such. We would love to hear comments on how we could better tag high-pressure materials
  • Begun enforcing the symmetry of the structure on piezo tensors. In general, this reduces the expected piezo value.

We’re onto to the second monthly release of our database. We continue to fix a lot of issues you’ve all flagged for us. Thank you for finding bugs. There are only a handful of developers in the Materials Project and we benefit immensely from the community. Please keep sending in bugs as you find them.

It’s also been pointed out that Materials Project has been running slowly for a number of people. We’ve had a sudden increase in load, likely due to the number of talks at MRS 2018 referencing Materials Project data for machine learning. We’re are working on scaling the website to cope with the load.


  • Adjusted the mp-id naming scheme to fix “mvc” ids taking over old mp-ids.
  • Fixed piezoeletric max_direction to be a miller index rather than a unit vector.
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We’re onto to our third release of our database which is coming a bit late, but we have a good excuse. Our dogs ate our database.

In reality, we’ve been preparing a major increase in the material count by a little over 47,000 new materials. These come primarily from finding orderings of many disordered structures in the ICSD as well as some structures originally from the Pauling files. We continue to use our structure matcher to ensure we’re not duplicating materials so the current set should offer good coverage of both the ICSD and Pauling files.

We’re onto the V2019.05 release of the MP Database. The last release (V2019.02) introduced a number of new compounds, but unfortunately also highlighted a validation issue for us that has actually been present for a while now in MP. The issue was this: Most of our structure optimizations show very small changes in the input volume, keeping the k-points consistent. However, for a number of new compounds, the volume change was significant – greater than 50% – which drastically changed the k-points necessary for proper coordinates and energies. These outlier compounds were not being caught before.

Rather than just removing them completely, we’ve built a deprecation tag to softly “remove” such materials from searches and phase diagrams. Exploring MP via the website will not show these materials, but you can still find them by ID via the API and by direct links; if a material was referenced in a publication, its data is still accessible.