In these materials the hydrogen atom is viewed as a pseudohalide.

There are more stages involved here than I've got time to tell you about, but basically we drive through the space, we populate it with environmental variables sulphide, halide, things like that.

The general formula for such an acyl halide can be written RCOX, where R may be, for example, an alkyl group, CO is the carbonyl group, and X represents the halide, such as chloride.