Most industrially used magnesium hydroxide is produced synthetically. Acetic acid is produced industrially both synthetically and by bacterial fermentation. Adhesives may be found naturally or produced synthetically. DIPEA is synthetically produced and commercially available. They are photosensitizing agents found in plants naturally and manufactured synthetically. Irish verb forms are constructed either synthetically or analytically. The condensation reaction is used to synthetically produce nylon polymers in industry. Olefins, especially diolefins, are effective ligands that afford synthetically useful derivatives. Sulfonium ylides are key intermediates in the synthetically useful Stevens rearrangement. It can also be produced synthetically. Only under Lewis acid catalysis do these reactions occur under synthetically useful conditions. Vegetarian pet food companies try to correct these deficiencies by adding synthetically produced nutrients. Multistriatin is a pheromone produced by female elm bark beetles, which can be produced synthetically. This was seen in both natural plants emitting the fragrance and emitting the scent synthetically. There have been attempts to synthetically manufacture spider silk.