【摘要】 祁连山石是在我国青海省发现的一种新的硼碳酸盐矿物,已由国际矿物学会新矿物和矿物命名委员会批准。该矿物的晶体结构中,重碳酸根和正硼酸分子之间由氢键联接,其分布具有带状特征,是一种新的结构类型。更多还原

【Abstract】 Qilianshanite is a new mineral found in Qinghai Province, China. The formula is NaHCO3·H3BO3· 2H2O. It is monoclinic, with α=1.6119(8), 6=0.6928(4), c = 0.6730(3) nm and β=100.46(4)° as determined and refined on the 4-circle diffra-ctorneter. The space group is C2. The stomic coordinates and thermal vibration parameters of all the nonhydrogen atoms were determined by the crystal structure analysis, with the R factor= 0.068. Sodium ions, bicar-bonate triangles and orthoboric acid triangle groups are all distributed on the ac planes with Y=0 or 1/2 to form layers. The structure can be regarded as a stack of layers linked by water molecules with hydrogen bonds. The Na cations, Na( 1 ) and Na( 2 ), coordinate with O atoms of bicarbonate groups and water molecules to form slightly distorted octahedra [Na O2 (H2O)4]·[HCO3] and [H3BO3] groups are connected by two hydrogen bonds to form endless [HCO3] [H3BO3] bands extending parallely to the c axis, which is a new hydrogen-bond configuration of inorganic carboborate salts.更多还原