BARIUM SELENATE

Description

Barium selanate has the molecular formula of BaSeO4 and the molecular weight of 280.2748 g/mol. It can be prepared by reacting sodium selenate with barium chloride in solution:
BaCl2(aq)+ Na2SeO4(aq) ? BaSeO4+ 2NaCl(aq)
Barium selenate is slightly soluble in water at 0.0052 g/100 ml at 20°C. Its CAS number is 7787-41-9. It is a white rhombic crystal which decomposes when heated beyond about 425°C. It is slightly soluble in water at 0.0152 g/100 ml at 20°C. Its solubility product is 3.40×10^-8.
The heat of formation of barium selenate is: △H₂₉₈ BaSeO4 = -249.0 kcal/mol (-1041.8 kJ/mol). As a result of the measurements, it has been found that for the reaction:
Basolid+ Sesolid+ 2O2 = BaSeO4
△H₂₉₈ = -279.2 cal/mol
△F₂₉₈ = -249.1 cal/mol

Chemical properties

orthorhombic crystal(s); preparation: heating BaCO3 and Se [MER06]

Reactivity Profile

Inorganic oxidizing agents can react with reducing agents to generate heat and products that may be gaseous (causing pressurization of closed containers). The products may themselves be capable of further reactions (such as combustion in the air). The chemical reduction of materials in this group can be rapid or even explosive, but often requires initiation (heat, spark, catalyst, addition of a solvent). Explosive mixtures of inorganic oxidizing agents with reducing agents often persist unchanged for long periods if initiation is prevented. Such systems are typically mixtures of solids, but may involve any combination of physical states. Some inorganic oxidizing agents are salts of metals that are soluble in water; dissolution dilutes but does not nullify the oxidizing power of such materials. Organic compounds in general have some reducing power and can in principle react with compounds in this class. Actual reactivity varies greatly with the identity of the organic compound. Inorganic oxidizing agents can react violently with active metals, cyanides, esters, and thiocyanates. Explosives often consist of an inorganic oxidizing agent mixed in intimate contact with a reducing agent. Gunpowder is such a mixture. Other examples are a mixture of sugar (an organic compound) plus sodium chlorate and magnesium (an inorganic reducing agent) plus barium peroxide.

Health Hazard

Highly toxic, may be fatal if inhaled, swallowed or absorbed through skin. Avoid any skin contact. Effects of contact or inhalation may be delayed. Fire may produce irritating, corrosive and/or toxic gases. Runoff from fire control or dilution water may be corrosive and/or toxic and cause pollution.

Fire Hazard

Non-combustible, substance itself does not burn but may decompose upon heating to produce corrosive and/or toxic fumes. Containers may explode when heated. Runoff may pollute waterways.