The purpose of this data file project is to gather thermodynamic data for biochemical and inorganic species available in the recent literature. The data files are available in comma-separated-value (CSV) and SUPCRT formats can be used in programs such as OrganoBIoGeoTherm. Find below a list of available files followed by notes on their format and composition.

Overview of files

• OBIGT.csv is a file in comma-separated-value format (suitable for import into spreadsheets) that contains the standard molal thermodynamic properties and equations of state parameters of over 2500 inorganic, organic, and biomolecular species and groups. It is the primary thermodynamic data file used in the CHNOSZ software package.
• OBIGT.dat is a sequential-access SUPCRT -format file derived from OBIGT.csv that is compatible with the OrganoBIoGeoTherm software package. For reasons of compatibility with SUPCRT format, this file contains a subset of the data found in OBIGT.csv. (In particular, phases whose heat capacity functions are expressed in terms beyond the three-term Maier-Kelley equation can not be shown in SUPCRT-format files. Also, two aqueous species (Am(Oxal)+ and Cm(Oxal)+) were excluded from OBIGT06.dat, because OrganoBIoGeoTherm does not recognize Am and Cm as elements.) NOTE: when importing this file into OrganoBioGeoTherm, be sure to specify the correct number of comment lines to skip (the number is given at the end of the file); otherwise you may encounter an "Invalid control array index" error.
• OBIGT-short.dat. Because of an unidentified format or length restriction, the CPRONS program that is part of the SUCPRT92 software package fails to operate with OBIGT.dat as input ... OBIGT-short.dat is a trimmed-down version that is compatible with SUPCRT92. (Data from the following sources were omitted: SK93, SK95, PSK99, HSS95, SS98, SSW+97. Refer to the slop98.dat datafile, available from GEOPIG, for a SUPCRT92-compatible file that contains these data.)
• sources lists the source keys and full references for thermodynamic data found in OBIGT.csv. A compact reference listing (not including titles of articles) is included with the *.dat files.
• units summarizes the units adopted for the properties and parameters found in OBIGT.csv.

Format of OBIGT.csv

• Each row represents the standard molal thermodynamic properties and equations of state parameters for a single species. The first 12 columns (name,abbrv,formula,state,source1,source2,date,G,H,S,Cp,V) are common to both aqueous and crystalline, gaseous, or liquid species. Missing values for any of these properties are denoted by NA.
• The meaning of the remaining columns depends on the physical state of the species. Missing values for these parameters are denoted by 0 or NA.
  • For aqueous species, the last columns represent a₁, a₂, a₃, a₄, c₁, c₂, and ω in the revised HKF equations of state. Note that these are scaled by the factors of 10 as shown on the units page.
  • For crystalline, gaseous, or liquid species, the remaining columns but the last represent coefficients (a, b, c, d, e f) in a polynomial equation for heat capacity as a function of temperature (see the page on units for more information). The last column (T) represents either the upper temperature limit for validity of the equation of state, or the transition temperature for species that undergo phase transitions.
• For minerals that undergo phase transitions, each phase is represented by a single species, with designations of state such as cr1, cr2, and cr3. In converting phase-transition data from SUPCRT format to that used in CSV file here, values of the standard molal thermodynamic properties of the cr2 and higher species at 25 C and 1 bar were by combining those of cr1 with the corresponding values representing the phase transition properties.
• Depending on usage, names are not necessarily unique (e.g., "water" and "steam" are the names for the liquid and gaseous states of H2O, but liquid and gaseous C6H14 are both called "3-methylpentane").

Notes on updates in 2008

• Added a header with reference information to the SUPCRT-format versions of the data file.
• Added the suffix ",g" to names of gases (so that in SUPCRT92 they can be distinguished from aqueous species of the same name).
• Added arsenious species and minerals from PPB+08, kerogens from HSR+08 and alkenes from Ric08.
• Corrected entry for Fe(OH)4-.

Notes on updates in 2007

• Added properties of aqueous disulfide species and crystalline amino acids and protein groups from Dick07.
• Added gaseous NO and N2O from AS01.
• Added species from CSM+07, ZKO06, TZS+07, MA07, HPT06.
• Updated volumetric ("a") parameters of acetic acid from ZKO06; changed c1, c2, omega of Ge(OH)4(aq) following PRH+05.

Notes on updates in 2006

• Many of the entries in OBIGT.csv were adapted from the slop98.dat datafile from GEOPIG. In addition, recent values generated by Prediction Central for proteins, nucleotides and other biochemical species are included. Some recent data for other organic and inorganic species from other laboratories are included.
• The properties and parameters of aqueous proteins (e.g., "AMY-PYRFU", "AMY-BACSU", "LYSC-CHICK") were calculated using the sidechain and backbone group contributions given in DLH06.
• The properties of the aqueous organic species in Table 17 of AH97a were recalculated using the group values presented in that paper and updated by DLH06 (except for the experimentally-derived properties of a number of low-carbon-number molecules - methane, benzene, methanol, methanamine - in AH97a). The updates in DLH06 to the organic group contributions alter the equations of state parameters, but not the values of G, H, S at 25 deg C and 1 bar.
• Superseded data: S(cr); updated using values found in petroleum.dat (citing Gurrieri, 1996). B(OH)3(aq); PSS95 supersedes SHS89. Aqueous acetamide, n-alkanes (n=8), alkylbenzenes (n=9), alcohols (n=8), amines (n=8); calculated using groups of AH97b and updated in DLH06; supersedes Sho93, SH90. Aqueous amino acids (n=15); DLH06 supersedes SH90. AlO2-, Al+3; TS01 supersedes SSW+97. Aqueous CH4, NH3, CO2, H2S, SO2; SSW01 supersedes SHS89, SH90 (c1, c2, omega). Gaseous CH4; HOK+98 supersedes WEP+82. Aqueous alanate, glycinate; AH97 supersedes SK95 (G, H, S). G, H, and S of the aqueous metal-amino acid complexes were recalculated from the values given in SK95 by taking account of the updated values for glycinate and alanate. aqueous carboxylic acids; values from Sho95 (calculated from experimental data and correlation algorithms) are retained (instead of those calculated from the groups of AH97b/DLH06).
• Properties of B species are taken from AVZP06, and those of some Ag, Cu and Au aqueous species from AZ01. The latter values supersede those for some Ag, Cu and Au complexes from SSH97.
• Properties of aqueous HCl are taken from TZA97 (supersedes the slop98/MS97 values). Properties of aqueous CaOH+ are taken from AZ99 (supersedes those of SSW97).
• The value of omega calculated for aqueous organic molecules using the groups of DLH06 are independent of the number of -CH2- groups present. (this approximation echoes the decreasing, then increasing trend (starting at about carbon number 5) in omegas of carboxylic acid used by Sho95, but is in contrast to the steadily decreasing values calculated using the groups given by AH97b.)