This is because the reactions that form HNC can often also form HCN, and vice versa, depending on the conditions in which the reaction occurs, and also that there exist isomerization reactions for the two species.
これは、HNCを生成する反応ではしばしばHCNも生じ、反応が起こる条件に依存して、両者の異性化反応も存在するためである。