Potassium+Bromide

Potassium Bromide is commonly used for infrared transmission windows in gas and liquid sample cells used with infrared and FTIR spectrophotometers and for beam splitters for spectrophotometers. KBr windows are soft and hygroscopic.ICL is the only company in the United States that grows KBr.



=Optical Properties--Potassium Bromide (KBr) Optical Crystals = Transmission Range: 230nm to 25µm Refractive Index: 1.524 at 11µm Reflection Loss: 8.4% at 10 µm ( 2 surfaces) =Physical Properties--Potassium Bromide (KBr) Optical Crystals = Melting Point: 730° C  Young's Modulus: 26.8 GPa Apparent Elastic Limit: 160 psi Structure: Cubic- (100) cleavage plane =Chemical Properties--Potassium Bromide (KBr) Optical Crystals = Solubility: 53.4gm/ 100gm H2O at 0° C

Medical and veterinary
The anticonvulsant properties of potassium bromide were first noted by Sir Charles Locock at a meeting of the [|Royal Medical and Chirurgical Society] in 1857. Bromide can be regarded as the first effective medication for [|epilepsy]. At the time, it was commonly thought that epilepsy was caused by masturbation. [|[1]] Locock noted that bromide calmed sexual excitement and thought this was responsible for his success in treating seizures. In the latter half of the 19th century, potassium bromide was used for the calming of seizure and nervous disorders on an enormous scale, with the use by single hospitals being as much as several tons a year (the dose for a given person being a few grams per day). [|[1]] There would not be a better drug for epilepsy until [|phenobarbital] in 1912. It was often said the [|British Army] laced soldiers' [|tea] with bromide to quell sexual arousal, but as doing so would also diminish alertness in battle it is likely to be an [|urban legend] and similar stories were also told about a number of substances. [|[2]] Bromide compounds, especially [|sodium bromide], continued to be used in over-the-counter sedatives and headache remedies (such as the original formulation of [|Bromo-Seltzer] ) in the United States until 1975 when bromides were withdrawn as ingredients in all over-the-counter medicinal formulations, due to the chronic toxicity of bromide. [|[3]] Bromide's exceedingly long half life in the body made it difficult to dose without side effects (see below). Medical use of bromides in the United States was discontinued at this time, as well, as many better and shorter-acting sedatives were known by that time. Potassium bromide is presently in the veterinary medicine field to treat epilepsy in dogs, either as first-line treatment or in addition to phenobarbital, when seizures are not adequately controlled with phenobarbital alone. Use of bromide in cats is limited because it carries a substantial risk of causing lung inflammation (pneumonitis) in this species. The use of bromide as a treatment drug for animals means that veterinary medical diagnostic laboratories are able as a matter of routine to measure serum levels of bromide on order of a veterinarian, whereas human medical diagnostic labs in the United States do not measure bromide as a routine test. Potassium bromide is not approved by the US [|Food and Drug Administration] (FDA) for use in humans to control seizures. In Germany, it continues to be approved for use as an antiepileptic drug for humans, particularly children and adolescents. These indications include severe forms of generalized tonic-clonic seizures, early-childhood-related Grand-Mal-seizures, and also severe myoclonic seizures during childhood. Adults who have reacted positively to the drug during childhood/adolescence may continue treatment. Potassium bromide tablets are sold under the brand name //Dibro-Be mono// (Rx-only). The drug has almost complete bioavailability, but the bromide ion has a relatively long half life of 12 days in the blood, [|[1]] making bromide salts difficult to adjust and dose. Bromide is not known to interfere with the absorption or excretion of any other anticonvulsant, though it does have strong interactions with chloride in the body, the normal body uptake and excretion of which strongly influences bromide's excretion. [|[1]] The therapeutic index (ratio of effectiveness to toxicity) is very small for bromide. As with other antiepileptics, sometimes even therapeutic doses (3 to 5 grams per day, taking 6 to 8 weeks to reach stable levels) may give rise to intoxication. Often indistinguishable from 'expected' side-effects, these include: depression, [|lethargy], [|somnolence] (from daytime sleepiness to [|coma] )loss of appetite and [|cachexia] , nausea/emesis with [|exicosis] (loss of body fluid)loss of [|reflexes] or pathologic reflexes [|clonic seizures][|tremor][|ataxia] loss of neural sensitivity [|paresis][|cerebral edema] with associated headache and [|papilledema] of the eyes [|delirium] : confusion, abnormal speech, loss of concentration and memory, aggressiveness [|psychoses]
 * // [|Bromism] // These are central nervous system reactions. They may include:
 * Acne-form dermatitis and other forms of skin disease may also be seen, as well as mucous hypersecretion in the lungs. Asthma and rhinitis may worsen. Rarely, tongue disorder, aphten, bad breath, and obstipation occur.

Optics
Potassium bromide is transparent from the near [|ultraviolet] to long wave [|infrared] [|wavelengths] (0.25-25 µm) and it has no significant [|optical absorption] lines in its high transmission region. It is used widely as infrared optical windows and components for general spectroscopy because of its wide spectral range. In [|infrared spectroscopy], samples are analyzed by grinding with powdered potassium bromide and pressing into a disc. Alternatively, the samples may be analyzed as a liquid film (neat, as a solution, or in a mull with [|Nujol] ) between two polished potassium bromide discs. [|[4]] Due to its high solubility and [|hygroscopic] nature it must be kept in a dry environment. The [|refractive index] is about 1.55 at 1.0 µm.

Photography
In addition to the manufacture of silver bromide previously mentioned, potassium bromide is used as a restrainer in black and white [|developer] formulas. It improves the differentiation between exposed and unexposed crystals of silver halide and thus reduces fog. [|[5]]