diff --git a/CHANGELOG.md b/CHANGELOG.md
index cf7a846..081addd 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 ## [Unreleased]
 ### Added
 - `equality` operator overload
+- `chemical_formula` attribute
 ## [0.1] - 2024-11-27
 ### Added
 - `MeltingTemperature` enum