CsI crystal
| |
Scintillating CsI crystal
| |
Crystal structure
| |
Names | |
---|---|
IUPAC name
Caesium iodide
| |
Other names
Cesium iodide
| |
Identifiers | |
3D model (
JSmol)
|
|
ChemSpider | |
ECHA InfoCard | 100.029.223 |
EC Number |
|
PubChem
CID
|
|
RTECS number |
|
UNII | |
CompTox Dashboard (
EPA)
|
|
| |
| |
Properties | |
CsI | |
Molar mass | 259.809 g/mol [2] |
Appearance | white crystalline solid |
Density | 4.51 g/cm3 [2] |
Melting point | 632 °C (1,170 °F; 905 K) [2] |
Boiling point | 1,280 °C (2,340 °F; 1,550 K) [2] |
848 g/L (25 °C) [2] | |
-82.6·10−6 cm3/mol [3] | |
Refractive index (nD)
|
1.9790 (0.3 µm) 1.7873 (0.59 µm) 1.7694 (0.75 µm) 1.7576 (1 µm) 1.7428 (5 µm) 1.7280 (20 µm) [4] |
Structure | |
CsCl, cP2 | |
Pm3m, No. 221 [5] | |
a = 0.4503 nm
| |
Lattice volume (V)
|
0.0913 nm3 |
Formula units (Z)
|
1 |
Cubic (Cs+) Cubic (I−) | |
Thermochemistry | |
Heat capacity (C)
|
52.8 J/mol·K [6] |
Std molar
entropy (S⦵298) |
123.1 J/mol·K [6] |
Std enthalpy of
formation (ΔfH⦵298) |
−346.6 kJ/mol [6] |
Gibbs free energy (ΔfG⦵)
|
-340.6 kJ/mol [6] |
Hazards | |
GHS labelling: | |
Warning | |
H315, H317, H319, H335 | |
P201, P202, P261, P264, P270, P271, P272, P273, P280, P281, P301+P312, P302+P352, P304+P340, P305+P351+P338, P308+P313, P312, P321, P330, P332+P313, P333+P313, P337+P313, P362, P363, P391, P403+P233, P405, P501 | |
Flash point | Non-flammable |
Lethal dose or concentration (LD, LC): | |
LD50 (
median dose)
|
2386 mg/kg (oral, rat) [1] |
Related compounds | |
Other
anions
|
Caesium fluoride Caesium chloride Caesium bromide Caesium astatide |
Other
cations
|
Lithium iodide Sodium iodide Potassium iodide Rubidium iodide Francium iodide |
Except where otherwise noted, data are given for materials in their
standard state (at 25 °C [77 °F], 100 kPa).
|
Caesium iodide or cesium iodide ( chemical formula CsI) is the ionic compound of caesium and iodine. It is often used as the input phosphor of an X-ray image intensifier tube found in fluoroscopy equipment. Caesium iodide photocathodes are highly efficient at extreme ultraviolet wavelengths. [7]
Bulk caesium iodide crystals have the cubic CsCl crystal structure, but the structure type of nanometer-thin CsI films depends on the substrate material – it is CsCl for mica and NaCl for LiF, NaBr and NaCl substrates. [9]
Caesium iodide atomic chains can be grown inside double-wall carbon nanotubes. In such chains I atoms appear brighter than Cs atoms in electron micrographs despite having a smaller mass. This difference was explained by the charge difference between Cs atoms (positive), inner nanotube walls (negative) and I atoms (negative). As a result, Cs atoms are attracted to the walls and vibrate more strongly than I atoms, which are pushed toward the nanotube axis. [8]
Т (°C) | 0 | 10 | 20 | 25 | 30 | 40 | 50 | 60 | 70 | 80 | 90 | 100 |
---|---|---|---|---|---|---|---|---|---|---|---|---|
S (wt%) | 30.9 | 37.2 | 43.2 | 45.9 | 48.6 | 53.3 | 57.3 | 60.7 | 63.6 | 65.9 | 67.7 | 69.2 |
An important application of caesium iodide crystals, which are scintillators, is electromagnetic calorimetry in experimental particle physics. Pure CsI is a fast and dense scintillating material with relatively low light yield that increases significantly with cooling. [11] It shows two main emission components: one in the near ultraviolet region at the wavelength of 310 nm and one at 460 nm. The drawbacks of CsI are a high temperature gradient and a slight hygroscopicity.
Caesium iodide is used as a beamsplitter in Fourier transform infrared (FTIR) spectrometers. It has a wider transmission range than the more common potassium bromide beamsplitters, working range into the far infrared. However, optical-quality CsI crystals are very soft and hard to cleave or polish. They should also be coated (typically with germanium) and stored in a desiccator, to minimize interaction with atmospheric water vapors. [12]
In addition to image intensifier input phosphors, caesium iodide is often also used in medicine as the scintillating material in flat panel x-ray detectors. [13]
CsI crystal
| |
Scintillating CsI crystal
| |
Crystal structure
| |
Names | |
---|---|
IUPAC name
Caesium iodide
| |
Other names
Cesium iodide
| |
Identifiers | |
3D model (
JSmol)
|
|
ChemSpider | |
ECHA InfoCard | 100.029.223 |
EC Number |
|
PubChem
CID
|
|
RTECS number |
|
UNII | |
CompTox Dashboard (
EPA)
|
|
| |
| |
Properties | |
CsI | |
Molar mass | 259.809 g/mol [2] |
Appearance | white crystalline solid |
Density | 4.51 g/cm3 [2] |
Melting point | 632 °C (1,170 °F; 905 K) [2] |
Boiling point | 1,280 °C (2,340 °F; 1,550 K) [2] |
848 g/L (25 °C) [2] | |
-82.6·10−6 cm3/mol [3] | |
Refractive index (nD)
|
1.9790 (0.3 µm) 1.7873 (0.59 µm) 1.7694 (0.75 µm) 1.7576 (1 µm) 1.7428 (5 µm) 1.7280 (20 µm) [4] |
Structure | |
CsCl, cP2 | |
Pm3m, No. 221 [5] | |
a = 0.4503 nm
| |
Lattice volume (V)
|
0.0913 nm3 |
Formula units (Z)
|
1 |
Cubic (Cs+) Cubic (I−) | |
Thermochemistry | |
Heat capacity (C)
|
52.8 J/mol·K [6] |
Std molar
entropy (S⦵298) |
123.1 J/mol·K [6] |
Std enthalpy of
formation (ΔfH⦵298) |
−346.6 kJ/mol [6] |
Gibbs free energy (ΔfG⦵)
|
-340.6 kJ/mol [6] |
Hazards | |
GHS labelling: | |
Warning | |
H315, H317, H319, H335 | |
P201, P202, P261, P264, P270, P271, P272, P273, P280, P281, P301+P312, P302+P352, P304+P340, P305+P351+P338, P308+P313, P312, P321, P330, P332+P313, P333+P313, P337+P313, P362, P363, P391, P403+P233, P405, P501 | |
Flash point | Non-flammable |
Lethal dose or concentration (LD, LC): | |
LD50 (
median dose)
|
2386 mg/kg (oral, rat) [1] |
Related compounds | |
Other
anions
|
Caesium fluoride Caesium chloride Caesium bromide Caesium astatide |
Other
cations
|
Lithium iodide Sodium iodide Potassium iodide Rubidium iodide Francium iodide |
Except where otherwise noted, data are given for materials in their
standard state (at 25 °C [77 °F], 100 kPa).
|
Caesium iodide or cesium iodide ( chemical formula CsI) is the ionic compound of caesium and iodine. It is often used as the input phosphor of an X-ray image intensifier tube found in fluoroscopy equipment. Caesium iodide photocathodes are highly efficient at extreme ultraviolet wavelengths. [7]
Bulk caesium iodide crystals have the cubic CsCl crystal structure, but the structure type of nanometer-thin CsI films depends on the substrate material – it is CsCl for mica and NaCl for LiF, NaBr and NaCl substrates. [9]
Caesium iodide atomic chains can be grown inside double-wall carbon nanotubes. In such chains I atoms appear brighter than Cs atoms in electron micrographs despite having a smaller mass. This difference was explained by the charge difference between Cs atoms (positive), inner nanotube walls (negative) and I atoms (negative). As a result, Cs atoms are attracted to the walls and vibrate more strongly than I atoms, which are pushed toward the nanotube axis. [8]
Т (°C) | 0 | 10 | 20 | 25 | 30 | 40 | 50 | 60 | 70 | 80 | 90 | 100 |
---|---|---|---|---|---|---|---|---|---|---|---|---|
S (wt%) | 30.9 | 37.2 | 43.2 | 45.9 | 48.6 | 53.3 | 57.3 | 60.7 | 63.6 | 65.9 | 67.7 | 69.2 |
An important application of caesium iodide crystals, which are scintillators, is electromagnetic calorimetry in experimental particle physics. Pure CsI is a fast and dense scintillating material with relatively low light yield that increases significantly with cooling. [11] It shows two main emission components: one in the near ultraviolet region at the wavelength of 310 nm and one at 460 nm. The drawbacks of CsI are a high temperature gradient and a slight hygroscopicity.
Caesium iodide is used as a beamsplitter in Fourier transform infrared (FTIR) spectrometers. It has a wider transmission range than the more common potassium bromide beamsplitters, working range into the far infrared. However, optical-quality CsI crystals are very soft and hard to cleave or polish. They should also be coated (typically with germanium) and stored in a desiccator, to minimize interaction with atmospheric water vapors. [12]
In addition to image intensifier input phosphors, caesium iodide is often also used in medicine as the scintillating material in flat panel x-ray detectors. [13]