Caesium chloride structure

A much less common structure for compounds of the form AX is the ceasium chloride structure:

"Body-centered cubic" would be inappropriate since it contains more than one type of atom. It is instead described as a primitive cubic structure of A interlocking with a primitive cubic structure of X. Here is another picture to make that clearer:

Caesium chloride structure

Ordinary caesium chloride is white powder with a rather low toxicity - used in alternative medicine as a cancer cure. Ceasium chloride with the radioactive Cs¹³¹ and Cs¹³⁷ isotopes are used in mainstream medicine. This is the stuff which resulted in the 1987 Goiânia accident (Goiânia is a state in Brazil):

That same day, scavengers Roberto dos Santos Alves and Wagner Mota Pereira entered the partially demolished facility, found the teletherapy unit--which they thought might have some scrap value, and took it home. They began dismantling the equipment. That same evening, they both began to vomit. They continued in their efforts. The following day, Pereira began to experience diarrhea and dizziness, and one of his hands began to swell. He soon developed a burn on this hand in the same size and shape as the aperture - one month later, the arm required amputation. Pereira visited a local clinic where his symptoms were diagnosed as the result of something he had eaten, and he was told to return home and rest. Alves continued with his efforts to dismantle the equipment.

Alves succeeded in puncturing the capsule's aperture window with a screwdriver, allowing him to see a deep blue light coming from the tiny opening he had created.He inserted the screwdriver and successfully scooped out some of the glowing substance. Thinking it was perhaps a type of gunpowder, he tried to light it, but the powder would not ignite.

Alves sold the items to a nearby scrapyard. The owner, Devair Alves Ferreira, noticed the blue glow from the punctured capsule. Thinking the capsule's contents were either valuable or supernatural, he brought it into his house. He invited friends and family to view the strange glowing substance. He mentioned that he intended to make a ring out of it for his wife. A friend of Ferreira's succeeded in freeing several rice-sized grains of the glowing material from the capsule using a screwdriver. He shared some of these with his brother, claimed some for himself, and the rest remained in the hands of Ferreira, who readily began to share it with various friends and family members. That same day, his wife began to fall ill.

Ivo, Devair's brother, scraped dust out of the source, taking it to his house a short distance away. There he spread some of it on the cement floor. His six-year-old daughter later ate a sandwich while sitting on the floor. She was also fascinated by the blue glow of the powder, and applying it to her body, showed it off to her mother. Dust from the powder fell on the sandwich she was consuming; she eventually absorbed 1.0 GBq, total dose 6.0 Gy.

Initially, when an international team arrived to treat her, she was confined to an isolated room in the hospital because the hospital staff were afraid to go near her.

She was buried in a special fiberglass coffin lined with lead to prevent the spread of radiation.