Possible Causes

1. File Path or Name Issue: Ensure the file path and name match the item registry name (`chemistrycraft:items\bottle_of_air.json`).

2. JSON Syntax Error: Verify the JSON syntax is correct (yours appears to be).

3. Missing Model Key: Although your file structure looks standard for item models, some model types might require a "model" key. Consider checking Minecraft Forge documentation or examples.