It decomposes without melting at 1124 °C into magnesium oxide (MgO) and sulfur trioxide (SO3). Heptahydrate
The heptahydrate takes its common name "Epsom salt" from a bitter saline spring in Epsom in Surrey, England, where the salt was produced from the springs that arise where the porous chalk of the North Downs meets the impervious London clay. The heptahydrate readily loses one equivalent of water to form the hexahydrate. It is a natural source of both magnesium and sulphur. Epsom salts are commonly used in bath salts, exfoliants, muscle relaxers and pain relievers. However, these are different from Epsom salts that are used for gardening, as they contain aromas and perfumes not suitable for plants. Monohydrate
Magnesium sulfate monohydrate, or kieserite, can be prepared by heating the heptahydrate to 120 °C. Further heating to 250 °C gives anhydrous magnesium sulfate. Undecahydrate
The undecahydrate MgSO4·11H2O, meridianiite, is stable at atmospheric pressure only below 2 °C. Above that temperature, it liquefies into a mix of solid heptahydrate and a saturated solution. It has a eutectic point with water at −3.9 °C and 17.3% (mass) of MgSO4. Large crystals can be obtained from solutions of the proper concentration kept at 0 °C for a few days.At pressures of about 0.9 GPa and at 240 K, meridianiite decomposes into a mixture of ice VI and the enneahydrate MgSO4·9H2O. Enneahydrate
The enneahydrate MgSO4·9H2O was identified and characterized only recently, even though it seems easy to produce (by cooling a solution of MgSO4 and sodium sulfate Na2SO4 in suitable proportions).
Rectal pain is the symptom of pain in the area of the rectum. A number of different causes (68) have been documented. Differential diagnosis
Anal fissures
One of the most common causes of rectal pain is an anal fissure. It involves a tear in the anal canal probably due to trauma from defecation and are usually treated effectively with sitz baths, stool softeners, and analgesics. LAS and proctalgia fugax
Two more highly common causes of functional anorectal pain are levator ani syndrome (LAS) and proctalgia fugax. Both of these conditions are thought to be caused by muscle spasms of the either the levator ani muscle or the anal sphincter muscle respectively, and may overlap symptomatically with a third less-common condition called coccygodynia which is the result of previous trauma to the coccyx bone. Stress, prolonged sitting, and constipation all seem to be associated with LAS. The majority (90%) of those reporting chronic episodes of such pain are women. Some researchers group these conditions under the medical category of "tension myalgia of the pelvic floor". Less than a third of those experiencing these conditions seek medical treatment for them. Treatment can involve the use of antispasmodic medications as well as the down-training (conscious involvement and relaxation of previously unconscious muscle movements) so that spasms occur less frequently or not at all. Anorectal abscess
An anorectal abscess is an infection that forms a pocket of pus within the tissues around the anus. It is treated surgically by incision and drainage.