Disodium enneaborate is the traditional name for a
salt
In common usage, salt is a mineral composed primarily of sodium chloride (NaCl). When used in food, especially in granulated form, it is more formally called table salt. In the form of a natural crystalline mineral, salt is also known as r ...
of
sodium
Sodium is a chemical element; it has Symbol (chemistry), symbol Na (from Neo-Latin ) and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 element, group 1 of the peri ...
,
boron
Boron is a chemical element; it has symbol B and atomic number 5. In its crystalline form it is a brittle, dark, lustrous metalloid; in its amorphous form it is a brown powder. As the lightest element of the boron group it has three ...
,
oxygen
Oxygen is a chemical element; it has chemical symbol, symbol O and atomic number 8. It is a member of the chalcogen group (periodic table), group in the periodic table, a highly reactivity (chemistry), reactive nonmetal (chemistry), non ...
, and
hydrogen
Hydrogen is a chemical element; it has chemical symbol, symbol H and atomic number 1. It is the lightest and abundance of the chemical elements, most abundant chemical element in the universe, constituting about 75% of all baryon, normal matter ...
, with
elemental formula
Amino acid-based formula is a type of infant milk formula made from individual amino acids. It is hypoallergenic and intended for infants suffering from severe allergy to milk and various gastrointestinal conditions, such as food protein-induce ...
or . It is the sodium borate with the highest boron/sodium ratio.
[
]
Structure
The correct formula has since been determined to be . The anion is a linear polymer with repeating unit . Sodium cations, water molecules, and undissociated boric acid
Boric acid, more specifically orthoboric acid, is a compound of boron, oxygen, and hydrogen with formula . It may also be called hydrogen orthoborate, trihydroxidoboron or boracic acid. It is usually encountered as colorless crystals or a white ...
molecules lie between the chains, held by numerous hydrogen bond
In chemistry, a hydrogen bond (H-bond) is a specific type of molecular interaction that exhibits partial covalent character and cannot be described as a purely electrostatic force. It occurs when a hydrogen (H) atom, Covalent bond, covalently b ...
s.[
The compound crystallizes in the ]monoclinic crystal system
In crystallography, the monoclinic crystal system is one of the seven crystal systems. A crystal system is described by three vectors. In the monoclinic system, the crystal is described by vectors of unequal lengths, as in the orthorhombic sy ...
with space group ''P''21/''n''. The cell parameters are ''a'' = 1021.3 pm, ''b'' = 1294.0 pm, ''c'' = 1245.7 pm, β = 93.070°, ''V'' = 1.6440 nm3, and ''Z'' = 2. The sodium cations occur in groups of four with interatomic distances of 378.30 pm and 379.32 pm.[
]
Reactions
Upon heating, disodium enneaborate initially becomes amorphous and then crystallizes as anhydrous disodium octaborate α- along with amorphous . Notably, the former contains octaborate fundamental building blocks that are topologically equivalent to those in the enneaborate.[
]
References
[Doinita Neiner, Yulia V. Sevryugina, Larry S. Harrower, and David M. Schubert (2017): "Structure and Properties of Sodium Enneaborate, Na2 8O11(OH)4�B(OH)3·2H2O". ''Inorganic Chemistry'', volume 56, issue 12, pages 7175–7181. ]
Borates
Sodium compounds
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