Table 2.

Definitions of entity, trigger word, and relation types, i.e., labels.

Label	Definition
Entity annotations
STARTING_MATERIAL	A substance that is consumed in the course of a chemical reaction providing atoms to products is considered as starting material.
REAGENT_CATALYST	A reagent is a compound added to a system to cause or help with a chemical reaction.
REACTION_PRODUCT	A product is a substance that is formed during a chemical reaction.
SOLVENT	A solvent is a chemical entity that dissolves a solute resulting in a solution.
OTHER_COMPOUND	Other chemical compounds that are not the products, starting materials, reagents, catalysts and solvents.
TIME	The reaction time of the reaction.
TEMPERATURE	The temperature at which the reaction was carried out.
YIELD_PERCENT	Yield given in percent values.
YIELD_OTHER	Yields provided in other units than %.
EXAMPLE_LABEL	A label associated with a reaction specification.
Trigger annotations
REACTION_STEP	An event within which starting materials are converted into the product.
WORKUP	An event step which is a manipulation required to isolate and purify the product of a chemical reaction.
Relation annotations
Arg1	The relation between an event trigger word and a chemical compound.
ArgM	The relation between an event trigger word and a temperature, time, or yield entity.