Ammonium hexafluorosilicate

Explosiveness

Link to relevant study record(s)

Reference

Endpoint:

explosive properties of explosives

Type of information:

other: Expert statement

Adequacy of study:

key study

Study period:

Study completion date - 13 June 2017

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Expert statement

Principles of method if other than guideline:

Expert judgment based on the screening procedure as described in:
- CLP, Annex I, Part 2, paragraphs 2.1.4.2 and 2.1.4.3
- Appendix 6 of the UN Recommendations on the Transport of Dangerous Goods, Manual of Tests and Criteria
- Technical Guidance Document on the Information Requirements for REACH, Part 2 EWG 1-7, REACH Implementation Project (RIP) 3.3 Phase 2, chapter 7.1.11.3

GLP compliance:

no

Key result

Parameter:

other: Determination of the exothermic decomposition energy

Remarks on result:

other: Analysis of the above depicted molecular structure revealed, that no such chemical alert structures are present in the molecule. Calculation of the oxygen balance was calculated to -26.94.

Screening evaluation

From literature Ammonium fluorosilicate is known to be noncombustible, but it will still release dangerous fumes in a fire, including hydrogen fluoride, silicon tetrafluoride, and nitrogen oxides¹. When heating up, the substance is known to decompose starting at about 140-150 °C emitting very toxic fumes of hydrogen fluoride, ammonia, and nitroxides^2,3,4. No information on explosive properties are available in literature. Considering that explosive properties are associated with the presence of certain chemical groups in the molecule, a screening evaluation can be conducted aimed to identify the presence of such reactive groups within the molecular structure harvesting the capability for a rapid high energy release. Analysis of the above depicted molecular structure revealed, that no such chemical alert structures are present in the molecule. Calculation of the oxygen balance was calculated to -26.94.

Determination of the exothermic decomposition energy

In this case this analysis is not possible since the substance composes at about 140-150 °C to release SiF4, HF and NH₃. Heating up to 350 °C will not result in the release of high energy peaks. The only energy released corresponds with substance decomposition energy. Due to safety reasons because of HF formed this analysis has not been performed and it is referred to literature data at this point. As a result the energy release is expected to be below a critical trigger level of 500 J/g with the onset of energy release being below 500 °C. In addition the dissociation reaction of (NH₄)₂SiF₆in SiF₄, 2NH₃and 2HFis endotherm (based on the thermodynamic calculation of the enthalpy of formation of the educts (compare data provided inCRC Handbook of Chemistry and Physics, 97th Edition⁵).

∑DM_fproducts - ∑DM_feducts = -12946.24 kJ/kg – (-15051.39 kJ/kg) = -2105.15 kJ/kg (or -2681 kJ/mol).

Interpretation of results:

GHS criteria not met

Conclusions:

The substance is considered to be non-explosive.

Executive summary:

No experimental test data according to EU Method A.14 or comparable methods are available for Reactive Blue 069. Hence an expert judgment based on the screening procedure as described in below mentioned guidelines was conducted:

- CLP, Annex I, Part 2, paragraphs 2.1.4.2 and 2.1.4.3

- Appendix 6 of the UN Recommendations on the Transport of Dangerous Goods, Manual of Tests and Criteria

- Technical Guidance Document on the Information Requirements for REACH, Part 2 EWG 1-7, REACH Implementation Project (RIP) 3.3 Phase 2, chapter 7.1.11.3

Analysis of the chemical structure reveals no alerts for explosive properties. Also data available in various databases do not contain any information about explosive properties of the substance. The calculation of a chemical oxygen balance gave a value of -26.94. The substance has been demonstrate to decompose starting at about 100-140 °C with no release of explosive of combustible gases and the energy release is expected to be below a critical trigger level of 500 J/g with the onset of energy release being below 500 °C since the enthalpy of formation is demonstrating the decomposition reaction to be endothermic. Therefore, the substance is considered to be non-explosive according to Directive 67/548/EEC and Regulation (EC) 1272/2008 and no further testing is required.

Description of key information

Ammonium hexafluorosilicate is considered to be non-explosive.

Key value for chemical safety assessment

Explosiveness:

non explosive

Additional information

No experimental test data according to EU Method A.14 or comparable methods are available for Reactive Blue 069. Hence an expert judgment based on the screening procedure as described in below mentioned guidelines was conducted:

- CLP, Annex I, Part 2, paragraphs 2.1.4.2 and 2.1.4.3

- Appendix 6 of the UN Recommendations on the Transport of Dangerous Goods, Manual of Tests and Criteria

- Technical Guidance Document on the Information Requirements for REACH, Part 2 EWG 1-7, REACH Implementation Project (RIP) 3.3 Phase 2, chapter 7.1.11.3

Analysis of the chemical structure reveals no alerts for explosive properties. Also data available in various databases do not contain any information about explosive properties of the substance. The calculation of a chemical oxygen balance gave a value of -26.94. The substance has been demonstrate to decompose starting at about 100-140 °C with no release of explosive of combustible gases and the energy release is expected to be below a critical trigger level of 500 J/g with the onset of energy release being below 500 °C since the enthalpy of formation is demonstrating the decomposition reaction to be endothermic. Therefore, the substance is considered to be non-explosive according to Directive 67/548/EEC and Regulation (EC) 1272/2008 and no further testing is required.

Justification for classification or non-classification

The substance is considered to be non-explosive according to Directive 67/548/EEC and Regulation (EC) 1272/2008 and accordingly no classification is required.