Why is boron trifluoride easier to use as a diethyl ether complex than as a gas?

Boron trifluoride (${\text{BF}}_3$) is a colorless, pungent gas that is highly reactive and fumes in moist air. Because it is a Lewis acid, it readily forms donor-acceptor complexes (adducts) with compounds containing lone pairs of electrons, such as ethers.12

Using boron trifluoride as a diethyl ether complex is often preferred over the gaseous form because the complex is significantly easier to handle and store. While gaseous ${\text{BF}}_3$ is difficult to manage due to its reactivity and physical state, the etherate complex provides a more stable, liquid form of the reagent that can be measured and added to reactions with greater precision and safety. In these adducts, the boron atom transitions from a three-coordinated planar structure to a four-coordinated tetrahedral geometry by accepting an unshared pair of electrons from the ether oxygen atom.2