<P> Caesium chloride or cesium chloride is the inorganic compound with the formula Cs Cl . This colorless solid is an important source of caesium ions in a variety of niche applications . Its crystal structure forms a major structural type where each caesium ion is coordinated by 8 chlorine ions . Caesium chloride dissolves in water . Caesium chloride occurs naturally as impurities in carnallite (up to 0.002%), sylvite and kainite . Less than 20 tonnes of CsCl is produced annually worldwide, mostly from a caesium - bearing mineral pollucite . </P> <P> Caesium chloride is widely used medicine structure in isopycnic centrifugation for separating various types of DNA . It is a reagent in analytical chemistry, where it is used to identify ions by the color and morphology of the precipitate . When enriched in radioisotopes, such as CsCl or CsCl, caesium chloride is used in nuclear medicine applications such as treatment of cancer and diagnosis of myocardial infarction . Another form of cancer treatment was studied using conventional non-radioactive CsCl . Whereas conventional caesium chloride has a rather low toxicity to humans and animals, the radioactive form easily contaminates the environment due to the high solubility of CsCl in water . Spread of CsCl powder from a 93 - gram container in 1987 in Goiânia, Brazil, resulted in one of the worst - ever radiation spill accidents killing four and directly affecting more than 100,000 people . </P> <P> The caesium chloride structure adopts a primitive cubic lattice with a two - atom basis, where both atoms have eightfold coordination . The chloride atoms lie upon the lattice points at the edges of the cube, while the caesium atoms lie in the holes in the center of the cubes . This structure is shared with CsBr and CsI and many binary metallic alloys . In contrast, the other alkaline halides have the sodium chloride (rocksalt) structure . When both ions are similar in size (Cs ionic radius 174 pm for this coordination number, Cl 181 pm) the CsCl structure is adopted, when they are different (Na ionic radius 102 pm, Cl 181 pm) the sodium chloride structure is adopted . Upon heating to above 445 ° C, the normal caesium chloride structure (α - CsCl) converts to the β - CsCl form with the rocksalt structure (space group Fm 3m). The rocksalt structure is also observed at ambient conditions in nanometer - thin CsCl films grown on mica, LiF, KBr and NaCl substrates . </P> <P> Caesium chloride is colorless in the form of large crystals and white when powdered . It readily dissolves in water with the maximum solubility increasing from 1865 g / L at 20 ° C to 2705 g / L at 100 ° C. The crystals are very hygroscopic and gradually disintegrate at ambient conditions . Caesium chloride does not form hydrates . </P>

What is the coordination number of cs in cscl
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