Which was the first deliberately produced man made chemical compound? Scientific history has no definite answer to this question.
The few assumptions have been made in this regard point to Bronze. The first substance man prepared might have been a compound of two metals - copper and tin. We do not call it a chemical, because bronze which is the product of copper and tin is an Alloy.
In the early days, people first learned to smelt metals from their ores and only later with years of experience, learnt to fuse them with each other. Hence, at the dawn of civilization the first seeds of a branch of the future science of chemistry, now known as metal chemistry appeared.
The chemical structure of metal and non metal compounds usually depends on the nature of the valence elements contained in them. Like the molecule of common salt is made of positively univalent sodium and negatively univalent chlorine. The ammonia molecule NH3 similarly contains negatively trivalent nitrogen and three positively univalent hydrogen atoms.
The chemical compounds of metals usually do not obey the laws of valence, and their composition bears no identity to the reacting elements valency. Due to this reason, the formula of intermetallic compounds looks strange, like MgZn5, KCd7 etc. The same pairs of metals often give several intermetallic compounds, like sodium and tin form nine different combos.