Compositional Screening: Mapping Chemical Space

Compositional Screening: Mapping Chemical Space#

Now that you understand chemical filters and their ability to eliminate impossible combinations, it’s time to take a systematic approach to exploring specific regions of chemical space. Compositional screening is the process of comprehensively mapping all possible compositions within a defined chemical system—think of it as creating a detailed atlas of what’s chemically feasible.

From Filters to Systematic Exploration#

In the previous sections, we learnt:

  • How combinatorial explosion creates vast possibilities

  • How chemical filters eliminate the impossible

  • How to apply individual filters step by step

Compositional screening builds on these foundations to tackle a fundamental question: “Within a specific chemical system, what compositions are possible, and which ones actually exist?” It’s the difference between knowing that some materials might exist and systematically cataloguing what’s truly achievable.

What is Compositional Screening?#

Compositional screening involves:

  1. Defining a chemical system (e.g., Cu-Ti-O for oxide semiconductors)

  2. Generating all possible compositions within that system

  3. Applying comprehensive chemical filters to identify viable candidates

  4. Comparing with known materials from databases like the Materials Project

  5. Visualizing the results to understand the accessible compositional space

Why This Matters for Materials Discovery#

Consider searching for new solar cell materials in the Cu-Ti-O system:

  • Raw possibilities: Thousands of compositions

  • After chemical filtering: Hundreds of viable candidates

  • Known from experiments: Dozens of actual compounds

  • Gap analysis: Which filtered compositions haven’t been made yet?

This gap represents unexplored opportunities for new materials discovery. It’s where the next breakthrough might be hiding—compounds that are chemically sensible but simply haven’t been synthesised yet.

What You’ll Learn#

In this section, we’ll explore:

  • How to systematically generate compositional spaces

  • Advanced filtering using multiple oxidation state sets

  • Comparing theoretical predictions with experimental reality

  • Creating ternary phase diagrams to visualise chemical space

  • Using oxidation state probability analysis to refine predictions

  • Identifying the most promising unexplored compositions

The Cu-Ti-O Case Study#

We’ll use the Cu-Ti-O system as our example because it demonstrates:

  • Industrial relevance: Important for photocatalysis and solar cells

  • Chemical complexity: Multiple oxidation states and phases

  • Data availability: Well-studied with known Materials Project entries

  • Visual appeal: Perfect for ternary phase diagram visualisation

Building on Previous Knowledge#

This section builds directly on our previous work:

  • Combinatorial Explosion taught us the scale of chemical space

  • Chemical Filters showed us how to eliminate impossibilities

  • Compositional Screening now shows us how to map what remains

Tools You’ll Master#

By the end of this section, you’ll be comfortable with:

  • SMACT’s oxidation state filtering capabilities

  • Materials Project API integration for validation

  • Ternary plot visualisation of chemical spaces

  • Oxidation state probability analysis

  • Systematic comparison of theory vs. experiment

Ready to map your first chemical space? In the follow-along notebook, we’ll take you through a complete compositional screening workflow using the Cu-Ti-O system. You’ll learn to generate theoretical compositional spaces, apply chemical filters, query experimental databases, and create compelling visualisations that reveal opportunities for new materials discovery.

Open the companion notebook to begin your hands-on exploration of chemical space!

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