Strontium amidoborane, Sr(NH 2 BH 3 ) 2 , is synthesized by gently milling the powder mixtures of SrH 2 and ammonia borane (in a 1:2 molar ratio), followed by isothermally processing the postmilled mixtures at 45°C for 2 h. It is found that Sr(NH 2 BH 3 ) 2 crystallizes with a monoclinic structure in space group C2, with lattice parameters a ) 8.1660(4) Å, b ) 5.0969(3) Å, c ) 6.7258(4) Å, and ) 94.392(4)°, and with Z ) 2. In the structure, each Sr 2+ bonds with two [NH 2 BH 3 ] 2-ions with a Sr-N distance of 2.68 Å. Thermal analyses show that the decomposition of Sr(NH 2 BH 3 ) 2 into Sr(NBH) 2 and H 2 initiates at about 60°C and becomes violent as the temperature increases to 93°C in the heating process at a rate of 2°C min -1 . With the release of H 2 , a considerable amount of NH 3 and small amounts of B 2 H 6 are also emitted due to the decomposition of Sr(NBH) 2 .
Stoichiometric strontium-incorporated hydroxyapatite (Sr-HA) with different Sr concentrations [Sr/(Sr+Ca)] were synthesized using a wet chemical approach and characterized by X-ray diffraction, Fourier-transformed infrared absorption, X-ray photoelectron spectroscopy, and Rietveld Structure Refinement. The crystal lattice parameter, Sr distribution, chemical state of Sr, and also the relationships between their variations and the Sr concentrations have been intensively studied. The results show that both the crystal lattice parameters and crystal plane space of Sr-HA remarkably increase with the Sr concentration increasing. Whether Sr preferably occupies the Ca(I) site or Ca(II) site after incorporated into apatite lattice depends on the Sr number incorporated into apatite. All the Sr ions completely occupy the Ca(II) sites when the Sr concentration is below 5%. With the exception of partial Sr ions occupying the Ca(II) sites, the other Sr ions start to occupy the Ca(I) sites when the Sr concentration doped in HA is beyond 10%. The ratio of Sr ions occupying the Ca(I) sites increases with the further raising Sr concentration up to 20%. The Sr ions inherit the chemical state and environment of the original Ca(I) or Ca(II) site after incorporated into apatite.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.