Calcium sulfate dihydrate

Chemical properties

monoclinic; hardness 1.5–2.0 Mohs; lumps or white powder(s); used in manufacturing portland cement, plaster of paris and artificial marble [KIR78] [MER06] [STR93]

The Uses of Calcium sulfate dihydrate

Calcium Sulfate Dihydrate is obtained from gypsum, a naturally occurring compound. Also used in the preparation of calcium sulfate and calcium sulfoaluminate.

The Uses of Calcium sulfate dihydrate

Used in this determination of oxalates

Definition

A mineral that consists of calcium sulfate with water molecules attached, or the rock that consists primarily of this mineral.

Definition

Gypsum: a monoclinic mineralform of hydrated calcium sulphate,CaSO₄.2H₂O. It occurs in five varieties:rock gypsum, which is oftenred stained and granular; gypsite, animpure earthy form occurring as asurface deposit; alabaster, a purefine-grained translucent form; satinspar, which is fibrous and silky; andselenite, which occurs as transparentcrystals in muds and clays. It is usedin the building industry and in themanufacture of cement, rubber,paper, and plaster of Paris.

Hazard

Nasal symptoms.

Agricultural Uses

Selenite, which is a salt of selenic acid (H₂SeO₃), and very similar to sulphite, is made by the oxidation of selenium by nitric acid. The low solubility of ironselenite complexes is responsible for the non-toxic level of selenium in plants growing on acid soils having a very high total selenium content. Plants absorb selenite, but generally to a lesser extent, than selenate, which is another form of selenium.

Safety Profile

Human systemic effects by inhalation: fibrosing alveolitis ('growth of fibrous tissue in the lung), unspecified respiratory system effects, and unspecified effects on the nose. Questionable carcinogen with experimental carcinogenic data. Long considered a nuisance dust (dependmg on silica content). When heated to decomposition it emits toxic fumes of SO,. See also CALCIUM SULFATE, CALCIUM COMPOUNDS, and SULFATES.

Synthesis

Calcium sulfate dehydrate (CSD) was firstly synthesized via the reaction of H2SO4 and Ca(OH)2 using ethanol as morphology modifier.

Purification Methods

It loses only part of its H2O at 100-150o (see below). It is soluble in H2O and very slowly soluble in glycerol. It is insoluble in most organic solvents.