While V produces arms and ammunition, its sister hive world specialises in chemicals. Everything from ammonia to zirconocene dichloride is synthesised in its laboratory habitats. Storage vats hundred of metres tall soar from the tops of its sealed hives into the poisonous atmosphere that barely clings to the planet. Were it not for the huge reserves of petrochemicals, radioisotopes, and base chemicals, IX would be a barren rock, ignored by man. Instead it is a heaving hive world of choking industrial chemical processes.
IX was settled aggressively in the 32nd millennium, the Adeptus Terra keen to extract every last resource from the world. Like a swarm of locusts, landers descended with pre-fabricated laboratories, processors and habs all over the world. Over time the largest reserves attracted more and more plants, and soon the cities were being built higher and higher over the resources they craved. Hive world status was afforded in the 35th millennium, and the growth rate shows no sign of abating.
Even for a hive world, life is particularly harsh for the lowest strata of society, subjected as they are to pollutants of every hue and state. Mutation is rife, far beyond what would be tolerable on V or elsewhere in the Carthax Sector. Even in the hive cities, workers with mottled skin, webbed fingers and twisted faces are accepted as long as they can do their job. The Synthesisers of IX are not put out by such trivial cosmetic changes amongst their underlings. As long as the chemicals still flow they are content to hold truck with mutants. As one can imagine, this does not sit well with the Ministorum, and IX has allowed to continue its untangling of the sacred helix thanks only to powerful friends within the Adeptus Terra.