Talc (Mg3H2(SiO3)4)

Endpoint summary

Additional information

Physical and chemical properties

 

Talc (Mg3H2(SiO3)4)

1.Appearance

Talc is a white odourless powder at 20 degC and 101.3 kPa.

 

 2.Melting point

Above 900°C, talc progressively loses its hydroxyl groups .Above 1050°C, talc re-crystallises into different forms of enstatite (anhydrous magnesium silicate). Talc's melting point is at 1500°C.

 

3.Boiling point

In accordance with column 2 of Annex VII (required in Section 7.3) of REACH Regulation 1907/2006 the study does not need to be conducted if the melting point is above 300ºC. The melting point ofTalc (Mg3H2(SiO3)4 is >900 ºC therefore the study is not required.

 

4.Density

2.7 -2.8 

 

5.Vapour pressure

A QSAR method predicts the vapour pressure of this substance to be  1.48E-020 Pa at 25C.

 

6.Water solubility

Insoluble in water.Talc is practically insoluble in water.

Substance is predicted by QSAR method (EPI Suite v 4.1/WSKOW v1.42 ) to be slightly soluble ( 0.421 mg/l) in water.

 

7.Partition co-efficient

 

A reliable QSAR method predicts a value for the partition co-efficient (logKow) of -9.40 for this substance. 

 

8.Hydrolysis as a function of pH

 

According to “ANNEX VIII- STANDARD INFORMATION REQUIREMENTS FOR SUBSTANCES MANUFACTURED OR IMPORTED IN QUANTITIES OF 10 TONNES OR MORE , study for Hydrolysis as a function of pH does not need to be conducted if:

-the substance is  insoluble in water. Hydrolysis is not expected to be an important environmental fate process since this compound lacks functional groups that hydrolyze under environmental conditions. Hydrolysis is a chemical reaction during which molecules of water (H2O) are split into hydrogen cations (H+, conventionally referred to as protons) and hydroxide anions (OH−) in the process of a chemical mechanism).

Talc (Mg3H2(SiO3)4) is almost insoluble in water. 

On this basis, Talc (Mg3H2(SiO3)4) does not have a potential for Hydrolysis and Magnesium ion will not hydrolise. 

 9.Adsorption/desorption

The log of the adsorption coefficient (KOC) of Talc (Mg3H2(SiO3)4) was estimated to be log KOC = 1.5027 which is equal to a KOC value of 31.82 using the KOCWIN v2.00 QSAR method.

10.Dissociation constant

According to “ANNEX IX- STANDARD INFORMATION REQUIREMENTS FOR SUBSTANCES MANUFACTURED OR IMPORTED IN QUANTITIES OF 100 TONNES OR MORE, study for Dissociation constant does not need to be conducted if:

- The substance is insoluble in water.

Talc (Mg3H2(SiO3)4) is insoluble in water.

Therefore testing for Dissociation constant does not need to be performed.

 

11.Flammability

Talc (Mg3H2(SiO3)4 is an inorganic solid which is not combustible and is stable: Talc (Mg3H2(SiO3)4 can be used as a fire-extinguishing agent.

From the compositional description and the structural formula given, it can be concluded that this substance CAS 14807-96-6, (EINECS) 238-877-9 is not pyrophoric (will not ignite or emit flammable gases on contact with air, damp air, or water) nor does it exhibit the property of flammability (will not easily burn when ignited or contribute to the combustion of other materials). There are no functional groups or other structural alerts present that would support any concern that this substance should be classified as dangerous according to the criteria for evaluating flammability, which is furthermore confirmed by long term handling experience.

 

12. Flash point

 

Talc is the world’s softest mineral and also it is an inorganic compound (a compound of chemical elements containing no carbon atoms). Talc is inorganic substance and according “ANNEX VII - STANDARD INFORMATION REQUIREMENTS FOR SUBSTANCES MANUFACTURED OR IMPORTED IN QUANTITIES OF ONE TONNE OR MORE” the study does not need to be conducted if the substance is inorganic.

 

 

 

13.Explosiveness

There are no chemical groups associated with explosive properties present in the molecules.

From the compositional description and the structural formula given, it can be concluded that this substance CAS 14807-96-6 , (EINECS) 238-877-9 does not exhibit explosive properties (will not detonate or deflagrate, under conditions of excessive heating with or without confinement, impact, or friction to produce heat and or gas). There are no functional groups or other structural alerts associated with explosive properties or tendencies that would indicate that this substance will manifest explosive properties. Similarly, the calculated Oxygen Balance is less than -200 suggesting that testing need not be conducted and that a negative result can be predicted. Thus, this substance should not be classified as dangerous according to the criteria for explosivity, which is furthermore confirmed by long term handling experience.

 

 

14.Viscosity

Talc (Mg3H2(SiO3)4 is an inroganic solid substance and therefore viscosity is not applicable.

Talc (Mg3H2(SiO3)4) is solid which remains solid at temperatures significantly above room temperature.

   

15.Autoignition temperature

Spontaneous combustion will not occur. Talc (Mg3H2(SiO3)4 is an inert inorganic substance and does not contain any element which is capable of auto ignition.

A negative result is expected on the basis that the recommended test method (Method N.4 of the UN Transport of Dangerous Goods, Manual of Tests and Criteria, fourth revised edition, 2003 - Tremain 2010) would only give a positive result if the substance self ignited at a temperature below 400°C. 

16.Oxidizing properties

 

From the compositional description and the structural formula given, it can be concluded that this substanceCAS 14807-96-6 , (EINECS) 238-877-9 does not exhibit oxidizing properties (will not cause or contribute to the combustion of other materials by virtue of its own inherent oxidation or reduction potential). There are no functional groups or other structural alerts present that would indicate that this substance would promote oxidation and thus should not be classified as dangerous according to the criteria for evaluating oxidizing properties. Furthermore, this is confirmed by long term handling experience.

 

 

 Table    Summary of physico-chemical properties

 

Property	Value	References
Physical state	Solid	OSHA,2009
Substance type	Inorganic	OSHA,2009
Color	white powder	OSHA 2009
Molecular Weight	379.27g/mol	US EPA, 2011
Melting point	1500°C	ILO-ICSC, 2012
Vapour pressure	1.48E-020 Pa at 25C	USEPA, 2014
Water solubility	0.421 mg/l(mg/l (calculated)  <0.1mg/l	US EPA, 2014  ILO-ICSC, 2012
Partition coefficient n-octanol/water (log value)	log Kow=-9.40(calculated)	USEPA, 2014
Henry Law Constant	5.539E-029 atm-m3/mole (5.613E-024 Pa-m3/mole)	USEPA, 2014