Vibrational spectroscopy of the borate mineral henmilite Ca₂Cu[B(OH)₄]₂(OH)₄.
Henmilite is a triclinic mineral with the crystal structure consisting of isolated B(OH)(4) tetrahedra, planar Cu(OH)(4) groups and Ca(OH)(3) polyhedra. The structure can also be viewed as having dimers of Ca polyhedra connected to each other through 2B(OH) tetrahedra to form chains parallel to the C axis. The structure of the mineral has been assessed by the combination of Raman and infrared spectra. Raman bands at 902, 922, 951, and 984 cm(-1) and infrared bands at 912, 955 and 998 cm(-1) are assigned to stretching vibrations of tetragonal boron. The Raman band at 758 cm(-1) is assigned to the symmetric stretching mode of tetrahedral boron. The series of bands in the 400-600 cm(-1) region are due to the out-of-plane bending modes of tetrahedral boron. Two very sharp Raman bands are observed at 3559 and 3609 cm(-1). Two infrared bands are found at 3558 and 3607 cm(-1). These bands are assigned to the OH stretching vibrations of the OH units in henmilite. A series of Raman bands are observed at 3195, 3269, 3328, 3396, 3424 and 3501 cm(-1) are assigned to water stretching modes. Infrared spectroscopy also identified water and OH units in the henmilite structure. It is proposed that water is involved in the structure of henmilite. Hydrogen bond distances based upon the OH stretching vibrations using a Libowitzky equation were calculated. The number and variation of water hydrogen bond distances are important for the stability off the mineral.
Vibrational Spectroscopy of the Borate Mineral Priceite—Implications for the Molecular Structure
ABSTRACT Priceite is a calcium borate mineral and occurs as white crystals in the monoclinic pyramidal crystal system. We have used a combination of Raman spectroscopy with complimentary infrared spectroscopy and scanning electron microscopy with Energy-dispersive X-ray Spectroscopy (EDS) to study the mineral priceite. Chemical analysis shows a pure phase consisting of B and Ca only. Raman bands at 956, 974, 991, and 1019 cm−1 are assigned to the BO stretching vibration of the B10O19 units. Raman bands at 1071, 1100, 1127, 1169, and 1211 cm−1 are attributed to the BOH in-plane bending modes. The intense infrared band at 805 cm−1 is assigned to the trigonal borate stretching modes. The Raman band at 674 cm−1 together with bands at 689, 697, 736, and 602 cm−1 are assigned to the trigonal and tetrahedral borate bending modes. Raman spectroscopy in the hydroxyl stretching region shows a series of bands with intense Raman band at 3555 cm−1 with a distinct shoulder at 3568 cm−1. Other bands in this spectral region are found at 3221, 3385, 3404, 3496, and 3510 cm−1. All of these bands are assigned to water stretching vibrations. The observation of multiple bands supports the concept of water being in different molecular environments in the structure of priceite. The molecular structure of a natural priceite has been assessed using vibrational spectroscopy.
Socially responsible enterprise in Cuba: a positive role model for Corporate Social Responsibility?’
This article examines the unique institutional environment of socialist Cuba, where currently a process of controlled marketization and expansion of private enterprise is taking place. The article investigates business behaviour in Cuba with particular reference to implicit assumptions relating to socially responsible enterprise, or Corporate Social Responsibility (CSR) as the term is understood in Western Liberal Democracies. It draws upon a series of interviews with business practitioners and business commentators (both Cuban and non-Cuban residents on the island). The interviews focused on the participants’ awareness of business ethics and socially responsible enterprise, and the cultural differences in assumptions and expectations relating to the concept of CSR between the Cuban and non-Cuban interviewees. We find that Cuba at this early stage of tentative marketization presents a positive role model of socially responsible enterprise. Both the highly regulated State economy and the embedded norms and values of social equity that have emerged as a consequence of Cuba’s socialist revolution facilitate business social responsibility. The relevance of this research to current debates in relation to CSR is discussed and it is argued that capitalist economies may similarly benefit from tighter regulatory control and by cultivating more pro-social business norms that prioritise ethical over economic concerns.