Ammonium Pentaborate

The a-form, which crystallines as the kinetic product, is the commercial form of ammonium pentaborate tetrahydrate and the P-form is the thermodynamic product but is slow to crystalline. Its heat capacity has been measured over a broad temperature range (85). Solubihty data are given ia Table 9 and pH data ia Table 10. 

Ammonium pentaborate tetrahydrate is very stable ia respect to ammonia loss. On heating from 100 to 230°C, it loses 75% of its water content but less than 1% of the ammonia. At 200°C, under reduced pressure, the water content drops to 1.15 mol, but only 2% of the ammonia is lost (61). At still higher temperatures all ammonia and water are expelled to give boric oxide (125). 

Ammonium tetraborate tetrahydrate is prepared by crystallization from an aqueous solution of boric acid and ammonia having a B202 (NH4)20 ratio of 1.8 2.1. Ammonium pentaborate is similarly produced from an aqueous solution of boric acid and ammonia having a B202 (NH4)20 ratio of 5. Supersaturated solutions are easily formed and the rate of crystallization is proportional to the extent of supersaturation (130). A process for the production... 

Two triborate moieties may link together by sharing a common tetrahedral boron atom to form the pentaborate anions shown in Fig. 5. The pentaborate monoanion shown in Fig. 5a is observed in solution (see Fig. 2) and occurs in synthetic and mineral borates. Examples are the synthetic commercial ammonium pentaborate, NH4[Bs06(0H)4] 2 H2O [ = (NH4)20 5 B2O3 ... 

Many borates are known that contain non-metal cations. Examples include the ammonium borates [39], such as the commercial products ammonium pentaborate, NH4[B506(0H)4] 2 H2O, and ammonium tetraborate, (NH4)2 [6405(011)4] 2 H2O, both of which contain isolated borate anions shown above (Figs. 5a and 6a, respectively) [40]. Isolated borate anions containing more than six boron atoms are rare. However, the mineral ammonioborite [(NH4)3[Bi502o(OH)g] 4 H20 = (NH4)20 5 B2O3 2 2/3 H2O), which may be prepared synthetically by prolonged reflux of a saturated solution of ammonium pentaborate, contains the unusual isolated anion [Bi502o(OH)g] , shown in Fig. 10 [41]. This anion is not known to occur in any metal borate, its formation is apparently directed exclusively by the ammonium cations which can donate H-bonds to interstitial water and the borate structural unit. 

Compound Name Ammonium Hydroxide Hexamethylenetetramine Ammonium Acetate Ammonium Bifluoride Ammonium Sulfamate Ammonium Sulfamate Ammonium Benzoate Ammonium Bicarbonate Ammonium Dichromate Ammonium Bifluoride Ammonium Carbonate Ammonium Chloride Ammonium Citrate Ammonium Citrate Ammonium Pentaborate Ammonium Dichromate Nickel Ammonium Sulfate Ferric Ammonium Citrate Ferric Ammonium Oxalate Ferrous Ammonium Sulfate Ammonium Fluoride Ammonium Silicofluoride Ammonium Formate Ammonium Gluconate Ammonium Bicarbonate Ammonium Bifluoride Ammonium Sulfide Ammonium Hydroxide Ammonium Thiosulfate Ammonium Thiosulfate Ammonium Iodide Ferrous Ammonium Sulfate Ammonium Lactate Ammonium Lactate Ammonium Lauryl Sulfate Ammonium Molybdate Ammonium Chloride Nickel Ammonium Sulfate Ammonium Nitrate Ammonium Nitrate-Urea Solution Ammonium Oleate... 

Ammonium Oxalate Ammonium Oxalate Hydrate Ammonium Pentaborate Ammonium Pentaborate Tetrahydrate Ammonium Pentachlorozincate Ammonium Perchlorate Ammonium Peroxydisulfate Ammonium Persulfate Ammonium Phosphate Ammonium Phosphate, Dibasic Ammonium Rhodanate Ammonium Rhodanide Ammonium Silicofluoride Ammonium Stearate Ammonium Sulfamate Ammonium Sulfate Ammonium Sulfhydrate Solution Ammonium Sulfide Ammonium Sulfide Solution Ammonium Sulfite Ammonium Sulfocyanate Ammonium Sulfocyanide Ammonium Tartrate Ammonium Thiocyanate Ammonium Thiosulfate Ammonium Zinc Chloride Amorphous Phosphorus AMS... 

The SrO 3B203 4H20 compound, occurring as tunellite, can be synthesized from the reaction between ammonium pentaborate and strontium salts. It was the first borate to be identified as possessing the hexaborate anion (Section III,A). The pentahydrate, 1 3 5, is stable in the SrO-B203-H ) system within the temperature range 0-100°C. Several routes to its preparation have been reported (206), and its dehydration has recently been studied (197). 

Ammonium pentaborate (NH4)20 5B203 8H20 (64.6%) 120 10.9 Epoxy, urethane, coating... 

Myers, R.E., Dicksons, E.D., Licursi, E., and Evans, R. 1985. Ammonium pentaborate An intumescent flame retardant for thermoplastic polyurethanes, J. Fire Sci., November/December, 3(6), 432-449. 

Prolonged reflux of an aqueous slurry of ammonium pentaborate results in quantitative conversion to [NH4]3[Bi502o(OH)8]-4H20, also known as the mineral... 

Synonyms Ammonium biborate Ammonium boron oxide Ammonium decaborate Ammonium pentaborate Boric acid, ammonium salt... 

See Ammonium capryleth sulfate Ammonium PEG (450) lauryl ether sulfate. See Ammonium laureth-9 sulfate Ammonium pentaborate. See Ammonium borate... 

The action of ammonium pentaborate (APB) in polyamide-6 as glass former has been studied. The degradation of APB into boric acid and boron oxide provides a low melting glass at temperatures of interest and then the char formed by the degradation of polyamide-6 is protected by the glass that induces the fire-retardant... 

Ammonium pentaborate is used in polyurethane and epoxy coatings. 

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