CompoundLookup Search compounds by elements
COMPARISONS

CompoundLookup vs PubChem vs ChemSpider: What's the Difference?

Compare CompoundLookup with traditional chemistry databases and understand when to use each tool.

5 min read | Updated January 28, 2026

Chemistry Database Comparison

PubChem

What it is: The world's largest free chemistry database, maintained by NIH.

  • Comprehensive data (100+ million compounds)
  • Detailed compound properties
  • Bioassay data
  • Free and authoritative

Limitations:

  • Requires exact formula or name
  • No element-based search
  • Can be overwhelming for beginners

Best for: Detailed research when you know exactly what compound you're looking for.

ChemSpider

What it is: Royal Society of Chemistry's database with integrated data sources.

  • Aggregates multiple databases
  • Good structure search
  • Property predictions

Limitations:

  • Requires formula or structure
  • No element-based search
  • Some features require registration

Best for: Structure-based searches and property predictions.

CompoundLookup

What it is: The world's first element-based compound search engine.

  • Search by selecting elements (unique!)
  • No formula knowledge required
  • Intuitive periodic table interface
  • Perfect for exploration and learning

Limitations:

  • Less detailed property data
  • Links to PubChem for full details
  • Database still growing

Best for: Discovering compounds, learning chemistry, initial research when you don't know the formula.

When to Use Each Tool

Scenario Best Tool
Know the exact formula PubChem
Have a structure drawing ChemSpider
Want to explore element combinations CompoundLookup
Need detailed bioassay data PubChem
Learning chemistry CompoundLookup
Quick compound discovery CompoundLookup

The CompoundLookup Advantage

The key differentiator is simple: no other tool lets you search by elements.

Traditional workflow:

  1. Wonder what compounds C and N form
  2. Search "carbon nitrogen compounds" on Google
  3. Find scattered, incomplete information
  4. Manually search each formula in PubChem

CompoundLookup workflow:

  1. Click C, click N
  2. See ALL carbon-nitrogen compounds instantly

We're not replacing PubChem or ChemSpider— we're filling a gap they can't fill. Use CompoundLookup for discovery, then click through to PubChem for detailed data.

Try Element-Based Search