Calcium thiosulfate (CaO3S2) is a compound composed of calcium, oxygen, and sulfur. It is commonly used in the medical and agricultural industries as a fertilizer and a treatment for certain medical conditions.
| IUPAC Name | Calcium thiosulfate |
| Molecular Formula | CaO3S2 |
| CAS Number | 10124-41-1 |
| Synonyms | Calcium hyposulfite; Calcium thiosulphate; Calcium sulfhydrate; Calcium thiosulfonate |
| InChI | InChI=1S/Ca.H2O3S2/c;1-4(2)3/h;(H2,1,2,3)/q+2;/p-2 |
Calcium Thiosulfate Properties
Calcium Thiosulfate Formula
The chemical formula of calcium thiosulfate is CaS2O3. It indicates the type and number of atoms in a molecule. The formula can be used to determine the molar mass and other properties of the compound.
Calcium Thiosulfate Molar Mass
The molar mass of CaO3S2 is 152.18 g/mol. It is composed of one calcium atom, three oxygen atoms, and two sulfur atoms. The molar mass is an important property used in chemical calculations, such as determining the amount of a substance required to produce a certain reaction.
Calcium Thiosulfate Boiling Point
CaO3S2 does not have a definite boiling point as it decomposes before boiling. It starts to decompose at around 75°C and releases sulfur dioxide gas. The boiling point of a substance is the temperature at which it changes from a liquid to a gas at a certain pressure.
Calcium Thiosulfate Melting Point
The melting point of CaO3S2 is 155°C. At this temperature, the solid compound changes from a solid to a liquid. The melting point is an important property that is used to identify and classify substances.
Calcium Thiosulfate Density g/mL
The density of CaO3S2 is 2.67 g/mL. Density is the amount of mass per unit volume. The density of a substance can be used to determine if it will float or sink in another substance, such as water.
Calcium Thiosulfate Molecular Weight
The molecular weight of CaO3S2 is 152.18 g/mol. It is the sum of the atomic weights of all atoms in a molecule. The molecular weight is used to calculate various properties of a substance, such as its molarity or concentration.
Calcium Thiosulfate Structure
The structure of CaO3S2 is composed of one Ca2+ ion and one S2O32- ion. The thiosulfate ion has a central sulfur atom with four oxygen atoms bonded to it. Two of the oxygen atoms are double-bonded, and two are single-bonded.
Calcium Thiosulfate Solubility
CaO3S2 is slightly soluble in water, with a solubility of approximately 16 g/L at room temperature. It is more soluble in hot water than in cold water. Solubility is the maximum amount of a substance that can dissolve in a given solvent at a specific temperature and pressure.
| Appearance | White crystalline solid |
| Specific Gravity | 2.67 g/mL |
| Color | White |
| Odor | Odorless |
| Molar Mass | 152.18 g/mol |
| Density | 2.67 g/mL |
| Melting Point | 155°C |
| Boiling Point | Decomposes before boiling |
| Flash Point | Not applicable |
| Water Solubility | 16 g/L at room temperature |
| Solubility | Slightly soluble in water |
| Vapour Pressure | Not applicable |
| Vapour Density | Not applicable |
| pKa | 7.2 (thiosulfuric acid dissociation) |
| pH | 6.0-8.5 (1% aqueous solution) |
Calcium Thiosulfate Safety and Hazards
CaO3S2 is generally considered safe when handled and used appropriately. However, it may cause skin and eye irritation and respiratory distress if inhaled. It can also cause gastrointestinal irritation if ingested. When handling this compound, it is important to wear appropriate personal protective equipment, such as gloves and eye protection. In case of skin contact, it should be washed with plenty of water. In case of eye contact, it should be rinsed with water for at least 15 minutes. In case of ingestion or inhalation, seek medical attention immediately. CaO3S2 should be stored in a cool, dry, and well-ventilated area, away from incompatible materials.
| Hazard Symbols | Xi (Irritant) |
| Safety Description | Avoid breathing dust/fume/gas/mist/vapours/spray. Wear protective gloves/protective clothing/eye protection/face protection. |
| UN IDs | Not regulated |
| HS Code | 2832.10.00 |
| Hazard Class | 6.1 (toxic) |
| Packing Group | III |
| Toxicity | LD50 (oral, rat) 1,064 mg/kg; LC50 (inhalation, rat) >2,000 mg/m3 |
Calcium Thiosulfate Synthesis Methods
Various methods exist for synthesizing CaO3S2.
One method involves reacting Calcium Hydroxide (Ca(OH)2) with Na2S2O3 in water to produce CaO3S2 and Sodium Hydroxide (NaOH).
Another method involves reacting Calcium Sulfate (CaSO4) with Sodium Sulfite (Na2SO3) and Sulfur (S) in water to produce CaO3S2 and Sodium Sulfate (Na2SO4).
One can obtain CaO3S2 by reacting Sulfur (S) and Oxygen (O2) with either Calcium Oxide (CaO) or Calcium Carbonate (CaCO3) in water. This method produces CaO3S2, Calcium Sulfate (CaSO4), and Carbon Dioxide (CO2) as by-products.
To synthesize CaO3S2, one can react Na2S2O3 with Calcium Chloride (CaCl2) in water. This method produces CaO3S2 and Sodium Chloride (NaCl) as by-products.
Another method involves reacting Calcium Hydroxide (Ca(OH)2) with Sulfur Dioxide (SO2) and Oxygen (O2) in water to produce CaO3S2 and Calcium Sulfite (CaSO3) as by-products.
Calcium Thiosulfate Uses
CaO3S2 has various uses in different industries. Some of its uses include:
- Agriculture – Used as a fertilizer to provide calcium and sulfur to plants.
- Photography – Used as a fixing agent in photographic processing to remove excess silver halide from prints and negatives.
- Water treatment – Used to remove chlorine from water and to neutralize chlorine in wastewater.
- Medicine – Used as a treatment for cyanide poisoning, as it reacts with cyanide to form the less toxic thiocyanate.
- Industrial – Used in various industrial processes, such as pulp and paper manufacturing, oil refining, and textile processing.
- Food industry – Used as a food preservative to prevent the growth of bacteria and to maintain the freshness of food.
- Animal health – Used as a nutritional supplement for animals to provide them with calcium and sulfur.
- Cosmetics – Used in cosmetics as a hair conditioning agent and as a skin moisturizer.
Questions:
Q: Which is more soluble in water, calcium thiosulfate or strontium thiosulfate?
A: CaO3S2 is more soluble in water than strontium thiosulfate.
Q: Which would you expect to be more soluble in water, strontium thiosulfate or calcium thiosulfate?
A: CaO3S2 is expected to be more soluble in water than strontium thiosulfate.
Q: What makes up an atom of calcium thiosulfate dechlorination?
A: An atom of CaO3S2 dechlorination consists of one calcium atom, three oxygen atoms, two sulfur atoms, and two thiosulfate ions.
Q: How to identify calcium thiosulfate?
A: CaO3S2 can be identified through its physical and chemical properties, as well as through various analytical techniques, such as infrared spectroscopy and X-ray diffraction.
Q: What do the numbers mean in calcium thiosulfate?
A: The numbers in CaO3S2 refer to the number of atoms of each element present in the compound. For example, CaO3S2 indicates that there is one calcium atom, three oxygen atoms, and two sulfur atoms.
Q: What is calcium thiosulfate water treatment?
A: CaO3S2 is used in water treatment to remove chlorine from water and to neutralize chlorine in wastewater.
Q: Are there calcium thiosulfate tablets available?
A: Yes, CaO3S2 tablets are available as a nutritional supplement for animals, providing them with calcium and sulfur.